For context, the author of the linked post, Sam James, is a Gentoo developer.
Anyway, this is a disaster. It was extremely irresponsible to share the exploit with the world before the distributions shipped the fix. Who knows how many shared hosting providers were hacked with this.
It's also worrying that it seems there's no communication between the kernel security team and distribution maintainers. One would hope that the former would notify the latter, but apparently it's the responsibility of whoever finds the vulnerability.
i have no problem with disclosing a vulnerability 30 days after its patched in the thing you reported to. (in fact, for those unaware, this is the same policy that google's project zero uses: "90+30" https://projectzero.google/vulnerability-disclosure-policy.h...)
the real problem is:
>It's also worrying that it seems there's no communication between the kernel security team and distribution maintainers.
the reporter should not be the one responsible for reporting separately to every single downstream of the thing they found a vuln in.
what should be happening, as you allude to, is a communication channel between the kernel security team and distribution maintainers. they are in a much better position to coordinate and communicate with the maintainers than random reporters are.
the minute the patch landed in the kernel, a notification should have gone out from the kernel team to a curated list of distro security folk that communicated the importance of the patch, and that the public disclosure would be in 30 days.
If you just want to get a bug fixed that annoys you, it's of course out of scope.
If researchers want to showcase their ability (either individually or as an organization) to identify and address security vulnerabilities in complex multi-stakeholder environments, I very much expect them to figure this out. After all, it doesn't make much sense if a company, after commissioning a security review, needs to hire a different firm to handle the vendor interactions, so that identified issues are resolved with minimal impact to the business.
> a company, after commissioning a security review, needs to hire a different firm to handle the vendor interactions
These vendor interactions you're referring to are the company's customers, correct? Are you proposing the company hire another company to manage getting updates to their customers?
Agree, but then where does the accountability lie? Presumably with the kernel maintainers themselves, correct? SOMEONE dropped the ball here. If we can't point the finger correctly, that seems like a problem in of itself.
The kernel devs patched the kernel. The kernel devs have a pretty known, straightforward stance in how they ship fixes for anything, because anything in the kernel can be a security problem.
Distro maintainers can see kernel changes. Some distros aggressively track new changes. Others backport what they feel are relevant. Others don’t do either.
Users pick what distro they use, and how they set up their infra.
Maybe if I were paying for RHEL licenses I’d be eyeballing the money I pay and RHEL’s response time.
But the ownership here lies with system operators, who pick their infrastructure, who design their security model, and who build their operational workflows. This vuln is a great example: people who looked at shared untrusted workloads on a single kernel and said “Hell no” had a much calmer day than teams who thought that was a good idea.
The fact that you had to take a whole paragraph to explain the contortionist arrival at something that isn't even really super clear after you explained it (you kinda pointed the finger both at end users and at distro maintainers simultaneously) and essentially boils down to "well, you as the end user need to be following kernel CVE's and can't trust distro maintainers to do it" does in fact indicate that there is a deeper issue at play here. You might say "well, there's no implicit chain of trust here". You might be right, but is that really the most effective way of doing things? Of course Linux is Use it at your Own Risk, but is there not a concept of "we as a collective community should get together and try not to drop the ball on some serious shit?"
In terms of something actionable, and maybe someone more well versed in how the distros work can tell me why this is a bad idea, but shouldn't there be a documented process and channel for critical CVE's to be bubbled out to distro maintainers who then have some sort of SLA for patching them and sending them downstream to end users? Perhaps incentives are not aligned to produce this outcome.
To be more blunt: if you’re paying for a product, the vendor owes you whatever things they committed to. If you’re a Redhat customer and your agreed SLA with Redhat for this kind of security fix was passed by, go be mad at Redhat. (I don’t think Redhat is bad here, they’re just the vendor most known for a commercial offering from the lists here. I would say the same thing about Ubuntu Pro)
Otherwise, it’s on the end user. Distro volunteers don’t owe you anything. Kernel devs don’t owe you anything.
I don’t care about what would be the most effective way of doing things. I care about what folks involved actually owe to each other, and distro volunteers don’t owe users any kind of active chasing of remediation due to the user’s threat model.
The idea of making some kind of streamlined process that solves what you didn’t like about this vulnerability’s remediation is that it ignores basically all the complexity. Like “what about distros that don’t abide by embargoes” or “what distros count as ones that matter” or “what about all the vulns that aren’t in Linux, they’re in software that’s packaged across many operating systems”.
Right, you’re saying “system is working as designed”, and I’m agreeing, but I’m saying “the system as designed kind of sucks, how can we make it better”?
I disagree that it sucks. It leverages a ton of people putting in their time and resources, and relies on system operators being active participants.
This vulnerability is, for some threat models, a really big deal. A security group found the vulnerability. They disclosed it. It was patched.
Folks here have gotten all kinds of bent out of shape that the groups involved didnt do things in the way each internet commenter would have liked. But this is the system working.
> This vulnerability is, for some threat models, a really big deal.
This vulnerability is, for other threat models, a death sentence.
> A security group found the vulnerability. They disclosed it. It was patched.
It was patched only after some people who should have been notified well in advance happened to notice something was up. That is NOT HOW IT'S SUPPOSED TO WORK.
For as long as the unpatched window remains open, skids will mess around and break things. Organized crime teams will use it for some really nasty hacking/ransomware/exfil/extortion/whatever. I guarantee you, this vuln is powerful and widespread enough that intel orgs will use it to kill targets, if they haven't already been using it for years. And if they have, we can just bank on them pulling out all the stops to take advantage of the remaining time for wreaking havoc. Make a project out of it and see if you can guess some of the future headlines.
Certain folks might not care much because they are citizens of one or more of those orgs' nations, so those targets are welcome to die in their opinion. That's fine. You do you, I'll do me, we'll all just go on doing our thing. But it's all fun and games until the wrong target gets hit and now there's a pact between the Germans and the Austrians being invoked and a few dozen million Europeans die. Or a geopolitical hotspot flares up and overnight 20% of the global petroleum supply chain grinds to a halt. Use your imagination. This vuln is a digital magic wand that is trivially usable to cast Avada Kedavra and somebody neglected to tell 99.99% of the Good Guys about it.
How is this different from any other day? Because now we've got a world-changing vuln out in the wild with no distro mitigation on day 1, and who the hell knows how many unscrupulous actors poised to take advantage of it before the fun and games stops. There will be no adults in the room when the miscreants decide to deploy while they still can.
Is this vuln going to start the next world war? Probably not. I don't expect it to and I hope and pray it doesn't. But leaving a vuln like this undisclosed to the very people whose job it is to protect us all is playing with fire. Not matches; more like a 10-grams-less-than-critical mass of plutonium.
sam is right to be pissed and he's doing a very good job of hiding it, because he knows that his users are at the mercy of TPTB in the Linux kernel world. Somebody's head needs to roll for this, and I don't mean some dude the CIA wants to hax0r because he's next on the list.
Fwiw, I'm completely with you on this. The folks you're communicating with seem utterly miserable, and don't seem to be communicating in good faith.
Not sure what the solution could/should be, but surely there could be a better, easier mechanism for kernel to advise all distro maintainers who care, and for those distro maintainers to subscribe in some way. Whether any distro maintainers do so (let alone do something about the vuln notifications) would be entirely up to them. There could also be some easier way for end users to see what the distros' policies on this are, such that they can take that into account when selecting a distro.
It seems odd to call me utterly miserable and then suggest I’m not communicating in good faith.
We don’t have to agree, but the site rules are pretty clear that swipes like that aren’t ok.
That kind of distro maintainers and kernel devs communication path already exists: the linux-distros@ mailing list. But since anybody can read it, posting “hey everybody, this is a security patch” has basically the same effect as the security researcher posting, in terms of disclosing the vuln to bad actors.
Given that anybody can make a Linux distro, and Linux distros aren’t generally either capable or interested in background checking their teams or policing their individual security practice, it doesn’t seem possible to have a communication channel that distros can sign up for that lacks this problem.
Just as a purely intellectual exercise, what changes about this if we leave aside ideas of "owe," "deserve ," and "earn?"
There's not really an enforcement mechanism in FOSS like there is in capitalism world, it just comes down to what we want our part of the world to look like. So I think we'd think more clearly if we leave aside the ideas like "who owes who what." I think it's fun to imagine what sort of motivations and incentives there are if we put away the money ones.
"leave aside ideas of "owe," "deserve ," and "earn?""
Nonsensical string of words with no meaning.
If you want something that someone else isn't giving you, you have the option to try to do it yourself, or try to compel someone else to give you what you want somehow. Feel free to idk pay someone to track the kernel list and 4000 others and send you heads-ups? Try to pass a law to make people do what you want since you don't care about words like "owe"?
> If you want something that someone else isn't giving you, you have the option to try to do it yourself, or try to compel someone else to give you what you want somehow.
Yes, exactly, the opposite of paying, since when you pay someone something they owe you whatever you paid for.
If we leave aside owe, deserve, and own, we can start discussing things like what we want our kernel ecosystem to look like, how we can make it safer, etc, without being burdened by these concepts.
It's a simple intellectual exercise, that's all. If you're having a strong reaction to it, imo that'd make it even more fun for you to participate.
The real advantage of Microsoft is that there is someone you can sue!
Linux like every open source project is just a bunch of people who are YOLOing it. Not something you use for your fortune 500 critical mission infrastructure.
But from what I understand they were not given enough information to know if it was relevant or not. The commit message just said it reverted a change from another commit because there was "no benefit". From the patch itself, it is not at all evident that this is a fix for a critical security bug.
> The commit message just said it reverted a change from another commit because there was "no benefit". From the patch itself, it is not at all evident that this is a fix for a critical security bug.
If the commit message says it fixes a security bug, then bad actors immediately know there's a possible exploit there. So maybe it's intentional? (not familiar with the policy for this)
Then we’re back to the initial problem. How can you fix and then communicate to downstream about security vulnerabilities without exposing those vulnerabilities in an open source project? If you want to reach all your possible users you have to disclose the vulnerability.
The accountability fundamentally lies with the distro maintainers. They're the ones shipping a "product". Either they need to get agreements in place for advance notice, or correctly set expectations with their users that they won't get advanced notice.
They dropped the ball when the shipped supposedly secure systems where their method for getting alerted to security updates was "hope people reporting to upstream will also notice a mailing list that will alert them".
(Caveat: Distro's like Ubuntu advertise security updates so this is on them. I'm not sure Gentoo does that, if they don't well then no one dropped the ball because no one represented that Gentoo got prompt security updates).
All it takes is to be part of the Kernel security team. I am surprised that many commercial strong distributors just not care enough to join the Kernel security team. Hopefully a valuable lesson was learned and fixes are applied.
The distros dropped the ball. imho.
One of the (main) tasks of the distro is watching the changed of you upstream packages for important changes.
This is slightly complicated by the fact that the linux kernel considers all bugfixes security fixes, so it's quite a lot to read it all. But that's life. The kernel developers are not wrong as it's nearly impossible to be sure a bug in the kernel is not (also) a security problem.
I'd imagine it's not that they lacked the time to email linux-distros, but that they were unaware they were supposed to do so.
Feels like the more sensible process would be for kernel maintainers to announce when a version contains a fix for a high-impact security vulnerability and for distro maintainers to pay attention to that. Could be done without revealing what the vulnerability actually is in most cases, trusting the kernel maintainer's judgement. There does seem to be a public linux-cve-announce mailing list.
Why is it the job of the kernel to notify the distros? Why isn't it the job of the distros to keep up on upstream security disclosures?
Expecting a FOSS project to go track down all of its (millions of?) users seems like a very unreasonable expectation, and is well outside of their scope of responsibility.
People have gotten so used to the Github flavour of free-labour, social-network-style FOSS that they've forgotten what all those LICENSE files actually say, which is to make it explicitly clear that the devs are not responsible to you for your issues, up to and including the software setting your house on fire. If you don't like it, you don't have to use it.
> Why isn't it the job of the distros to keep up on upstream security disclosures?
They can't, because (responsible) security disclosures are private, _not public_.
That's the whole point of the system: notify the developers in private ahead of time (usually 30, 60 or 90 days) so they can write, test and roll-out the fixes before you release the info to the whole world. This is to minimize the time between when bad actors gain access to the exploits vs. when users install the patch.
So "keeping up on security disclosures" cannot ever be a 'pull' process.
Usually the maintainers of the big distros are part of (private) security mailinglists and receive such info. Just not in this case it seems.
The problem is that the kernel devs (correctly imo) consider all bugfixes security fixes. So the distros need to decide for themselves which ones are important enough to warrant an update. Apparently this one had a quite unclear commit message, so it importance was missed.
Not ideal, but also: shit happens? It's always a balancing act choosing the lesser of multiple evils and most of the time it seems to work ok-ish, which is probably the best we can hope for ;-P
The kernel maintainers don't flag "security fixes" as special, and they have a well-thought-out reason for that, see many other comments in this thread.
That, and they flag pretty much any random patch with a CVE these days, making it harder for distro maintainers to keep up.
For this specific "bug" they took care to not mention any security angle in the commit message, making it extremely hard for an outsider to even realize this was a critical patch. I assume this was because they wanted to push the fix without breaking embargo.
> Expecting a FOSS project to go track down all of its (millions of?) users seems like a very unreasonable expectation, and is well outside of their scope of responsibility.
The post you are responding to says that it would be nice if they copied literally one mailing list.
> a notification should have gone out from the kernel team to a curated list of distro security folk
Who would curate that list though? You don't need permission from the kernel team to spin up a new distro. I can go and create fork of Debian or Arch or whatever today and the kernel team would never know (and neither should they).
This is completely in the responsibility of the distros. If you don't like this model, use something like FreeBSD.
You don't need anyone's permission to make a distro, that's true, but if you notify Debian, Canonical, Fedora, Red Hat and Arch you're covering a very large fraction of users; way more than today's 0%. In cases like this, perfect is the enemy of the good.
A rogue actor may create a new distro, maybe for some niche use case such as accessibility or retro gaming. After acquiring enough false (and even some real) users that the Linux Foundation accepts them as a notifiable distro maintainer, this maintainer could then pwn machines before the exploit is made public.
Uh, there is a list, named "linux-distros", which is for this purpose (and I think it's for more than just Linux, e.g. I believe it was used for the xz vuln).
Given this was announced when backports weren't ready (and given the POC was at least opaque if not obfuscated), I'm getting the vibe fixing the vuln wasn't as high as a priority as making a media splash.
> Note that for Linux kernel vulnerabilities, unless the reporter chooses
> to bring it to the linux-distros ML, there is no heads-up to
> distributions.
so, no, `linux-distros` list don't solve the problem.
Microsoft has a long and sordid history of cheerfully doing anything they can to fuck everyone over just to make a few more percentage points of profit.
Linux is a free kernel that literally revolutionized the computing landscape.
It might be a scared cow, but at least deservedly so. There is imho a difference between accidental incompetence (debatable, even) and active malice. Microsoft has done a lot of the latter so gets bashed more, nor surprise there.
What process? Wasn't the default state of things to just let any random person of the street spam vulnerability reports without validation or quality control?
Two things can be true simultaneously: the Linux kernel ecosystem should have done better at communicating this to their downstreams, and publicly sharing the exploit was irresponsible.
It is not the responsibility of the initial reporter to communicate to distributions, but the fact that those responsible failed to do that, doesn't give everybody else a free pass.
No, this was already timed disclosure. This is very common and widely accepted. 90+30 is what Google Project Zero uses, for example. The security researcher has met their ethical requirements already. This is entirely on the kernel's security team for failure to communicate downstream. That is their responsibility.
The thing is, malicous actors are already monitoring most major projects and doing either source analysis or binary analysis to figure out if changes were made to patch a vulnerability. So, as soon as you actually patch, you really need to disclose because all you're doing by not disclosing the vulnerability is handing the bad actors a free go. The black hats already know. You need to tell the white hats, too, so they can patch.
I'm not advocating for delaying the disclosure at all; my point is, if you see your initial disclosure to the kernel didn't go anywhere, to be responsible is to put in a little extra effort to ensure the fix is picked up before you disclose.
"Didn't go anywhere"? The kernel devs patched it! They patched it weeks ago! The kernel security team needs to communicate security problems in their own releases, because that is where the distros are already looking.
Requiring the security researcher to do it is insane. Should a security researcher that identifies a vulnerability in electron.js need to identify every possible project using electron.js to communicate with them the vulnerability exists? No. That's absurd.
The kernel devs patched it! They patched it weeks ago
FTFA:
> I see that on the 11th of April 6.19.12 & 6.18.22 were released with the fix backported.
> Longterm 6.12, 6.6, 6.1, 5.15, 5.10 have not received the fix and I don't see anything in the upstream stable queues yet as I write.
I wouldn't go so far as to call this "the kernel devs patched it". Virtually none of the kernels that distro's are actually using today have received a fix. This looks like an extremely lackluster response from the kernel security team.
Pretty much the only non-rolling distro's that are shipping a fixed kernel are Fedora 44 and Ubuntu 26.04, both released in the last few weeks. Their previous releases both shipped with Linux 6.17 which is still vulnerable today!
None of this impacts disclosure norms. One important reason the clock starts ticking faster once any patch lands is that for serious attackers, the patch discloses the vulnerability. That's quadruply so in 2026, when many orgs are automatically pumping Linux patches through LLM pipelines to qualify them for exploitability.
But it's been at least 15 years since "reversing means patches are effectively disclosures legible mostly to attackers" became a norm in software security. And that was for closed-source software (most notably Windows). The norms are even laxer for open source.
> Should a security researcher that identifies a vulnerability in electron.js need to identify _every_ possible project using electron.js to communicate with them the vulnerability exists? No. That's absurd.
But this is a false comparison, right? The scope of "Linux distributions" and "electron apps" are orders of magnitude different. If the reporter spot checked one or two of the most popular distributions to see if fixes had been adopted, that seems like an extra level of nice diligence before publicizing the details.
It doesn't seem "insane" as much as "not the most efficient path" as has already been well argued. But it also doesn't seem unreasonable to think in a project of the scope of the Linux kernel, with the potential impact of fairly effective(?) privilege escalation, some extra consideration is reasonable--certainly not "insane" at the very least?
They embargoed their vulnerability for 30 days after Linux landed a kernel patch. They did their part. You will always be able to come up with other things they could do for you, and they will always at first blush sound reasonable because of how big and important Linux is, but none of those things will be responsibilities of the vulnerability researcher. Their job is to bring information to light, not to manage downstreams.
About half the thread we're on reads as if the commenters believe Xint made this vulnerability. They did not: they alerted you to it. It was already there.
I realize you've been championing this idea in the thread, and I admire it because I also recognize the misdirected blame. Please understand I do not harbor "blame" for the researchers.
> Their job is to bring information to light, not to manage downstreams.
The researchers are also members of a community in which more harm than is necessary may be dealt by their actions. Nuance must exist in evaluating "reasonable" and "responsible" in the context of actions.
I strongly disagree. I want the information. I don't want to wait longer to find out about critical vulnerabilities so that researchers can fully genuflect to whatever Linux distribution norms people on message boards have. Their "actions" were to disclose a vulnerability that already existed and was putting people at risk. It's an absolute good.
If it helps you out any, even though my logic was absolutely the same and just as categorical in 2012 as it is today: there are now multiple automated projects that run every merged Linux commit through frontier models to scope them (the status quo ante of the patch) out for exploitability, and then add them to libraries of automatically-exploitable bugs.
People here are just mad that they heard about the bug. Serious attackers had this the moment it hit the kernel. This whole debate is kind of farcical. It's about a "real time" response this week to a disaster that struck a month ago.
I do get that, this era of automation is too responsive to not go public to provoke action. I think I might just be wistful of an era in which the alternate path might have made a difference. Sorry to pile on.
they did it in the established industry standard way that probably every single security researcher you can think of follows (for good reason, i would add).
whoever did the marketing on "responsible disclosure" was a genius.
tptacek says it much better than me: ""Responsible disclosure" is an Orwellian term cooked up between @Stake and Microsoft and other large vendors to coerce researchers into synchronizing with vendor release schedules."
In my world, responsibility is not just checking a box of following industry practice. Responsibility, as Wikipedia puts it on their social responsibility page, is working together with others for the benefit of the community. And yes, sometimes that's a bit larger burden than would ideally be the case. It's an imperfect world, after all -- and let's not forget the disclosure as it happened also placed a larger burden than ideal on people scrambling to patch.
And it's not as if I'm asking for a lot of effort. One mail to the security team of a popular distro "hey, we have found this LPE that we'll release with exploit next week, it's patched upstream already in this commit, but you don't seem to have picked it up" would likely have been enough.
The problem is that vendors and developers have repeatedly shown that if you give them an inch, they take a mile. Look at exactly what happened with BlueHammer this month. The security researcher went full disclosure because Microsoft didn't listen to their reports.
Disclosure is vital. It's essential. Because the truth is, if a security researcher has found it, it's extremely likely that it's already been found by either black hats or by state actors. Ignorance is not actually protection from exploitation.
The security researcher also has a responsibility to the general public that is still actively using vulnerable software in ignorance. They need to be protected from vendor and developer negligence as well as from exploits. And the only way to protect yourself from an exploit that hasn't yet been patched is to know that it is there.
The situation with e.g. BlueHammer is fundamentally different: there, the only party that could act on it (Microsoft) ignored them. In this case, the parties that could act on it weren't notified at all.
I'm also not proposing delaying the disclosure to the general public at all. They already waited 30 days with that, that's fine. Just look a bit further than your checklist of only contacting upstream, and send a mail to the distributions if they haven't picked it up a week or two before.
Downstream vulnerability disclosure is a negotiation between the downstreams and the upstreams. It is not the job of a vulnerability researcher to map this out perfectly (or at all).
Yes and that's why the current system where security researchers are expected to reach out to the distro mailing list is flawed and instead there should be a defined pipeline for the kernel security team to give a heads up.
"Prior to Project Zero our researchers had tried a number of different disclosure policies, such as coordinated vulnerability disclosure. [...] "We used this model of disclosure for over a decade, and the results weren’t particularly compelling. Many fixes took over six months to be released, while some of our vulnerability reports went unfixed entirely! We were optimistic that vendors could do better, but we weren’t seeing the improvements to internal triage, patch development, testing, and release processes that we knew would provide the most benefit to users.
[...]
While every vulnerability disclosure policy has certain pros and cons, Project Zero has concluded that a 90-day disclosure deadline policy is currently the best option available for user security. Based on our experiences with using this policy for multiple years across thousands of vulnerability reports, we can say that we’re very satisfied with the results.
[...]
For example, we observed a 40% faster response time from one software vendor when comparing bugs reported against the same target over a 7-year period, while another software vendor doubled the regularity of their security updates in response to our policy."
>Linux distros (specifically) act in this way
carving out special exceptions based on nebulous criteria is a bad idea. 90+30 is what has been settled on, and mostly works.
Because I would call a situation where the development team fails to appreciate the severity of a security vulnerability and has an established procedure that requires the researcher and not the kernel team to communicate with downstream users is already a major failure of process. Security is not just patching the vulnerability, and it seems that the Linux kernel developers or the Linux kernel security team does not understand that.
This is the result of that failure.
If this were any other software, we'd be here with pitchforks and torches. The researcher gave the developers timed disclosure, and even waited until after the developers had patched the issue. And... it's still a problem.
If the maintainers were unresponsive, sure -- but it seems slightly hard to buy that a responsible reporter trying to make a big splash and a good impression wouldn't first check "did this make it out to the distros?" before making sysadmin's days real shitty, even if technically they could point fingers at other parties. At which point, if they're paying paying any attention at all to what they reported, they may have realized that a mistake was made.
its an industry standard disclosure process. 90 days after reporting, or 30 days after the patch lands, the vuln is disclosed.
the linux kernel team is in a 10000% better position to communicate to and coordinate their downstreams. it seems completely backwards to me to suggest that the reporter should be responsible for figuring out every possible downstream and opening up separate reports to each of them.
the kernel team should have a process/channel to say "this is important! disclosure is in 30 days" that is received by distro security teams. because this is not the first or last time the kernel will have a local privilege escalation. hoping that every reporter, forever in the future, will take the onus on themselves is a recipe for disapointment.
The problem is that if you make too big of a deal about a particular patch, then someone just reverse engineers the vuln from the fix and your responsible disclosure period doesn't exist anymore.
Gentoo has to take some blame too for not keeping all the kernels they maintain patched in a timely way.
> Gentoo has to take some blame too for not keeping all the kernels they maintain patched in a timely way.
How do you figure that? From what I could tell from the earlier post, the fix has only been backported to 6.18 and later, and as TFA indicates the distro's were not informed of the security implications of this fix. All distro's shipping a major kernel version from more than a year ago -- and that includes all LTS kernels -- are vulnerable, regardless of how "timely" their patch schedules follow upstream.
Yes, it's just incompetence from everyone involved, not malice. The company making the disclosure doesn't actually care, and the kernel processes are ineffective.
No, it's incompetence from everyone involved except the company making the disclosure, which, despite the fact that the existing norms are not in fact binding (like people downthread seem to believe), they followed.
`it's technically possible to pass the blame to other people` presupposes that the blame belongs to the reporter unless effort is taken to "shift" it. This is just an inaccurate worldview as many people have pointed out clearly in this discussion. If there's a vulnerability in software the blame lies with people who wrote and maintain the software, not someone who finds and discloses a vulnerability. The person who should `check in on the status of the fixes` is the person who owns the thing being fixed, which is very much the kernel and distro maintainers and not the security researcher. It is you who are willfully shifting blame to an innocent party
One of the reasons this unavoidable deadline was invented, is that the alternative is that one company (or all of them) can simply decide to ignore the vuln report, and then the vulnerability will stay forever undisclosed and forever out there in the wild. And prisoner's dilemma suggests that most companies would chose "do nothing" in this scenario: they don't have to do anything, and if the vuln stays undisclosed, it probably won't be exploited anyhow. Win-win!
I'm confused. Can you explain how this applies to the current situation, where no vuln reports were submitted to the groups responsible for distributing patches?
>where no vuln reports were submitted to the groups responsible for distributing patches?
the vulnerability report was submitted to the kernel security team and appropriate kernel maintainers. those are the people responsible for patching the kernel, which they did 30 days ago.
imagine you use a dependency in your code. like left-pad. and some vulnerability is found in left-pad.
is the reporter of that vulnerability responsible for finding and submitting a vulnerability report to every single piece of software that uses left-pad? all ~millions of them?
or do they submit the report to left-pad, get them to fix it at the source, and trust that the people relying on left-pad will update their software like they should when they see a security-relevant update is available?
I worked at the industry's first commercial vulnerability lab (Secure Networks) in the mid-90s, and many of my friends at the time founded X-Force. Commercial vulnerability research has always been about marketing: marketing pays for the vulnerability research. That doesn't make it any less prosocial.
hope you are also blacklisting google's project zero, and practically every other major player in the vulnerability reporting space, as all use roughly the same bog standard 90+30 policy.
this was a failure of the kernel security team, and their stance on communicating security issues with their downstreams.
Researchers are under no obligation to engage in coordinated disclosure and are free to sell 0day for profit. Just fyi. Be glad it was disclosed at all. Be glad a patch was available prior to release.
If they want to be seen as responsible rather than opportunistic, then yeah, they should do a proper coordinated disclosure.
Sure, they have no legal obligation to disclose, but we all also have no legal obligation to buy their services. Blacklisting bad actors like this is the right move to discourage this kind of behavior.
they did a proper coordinated disclosure, following the industry standard 90+30 process. that is why the exploit dropped 30 days after the patch landed.
the kernel team should have communicated with their downstream about the importance of the patch. that is the kernel security team's responsibility -- and they are much better positioned to do that than crossing your fingers and hoping every reporter will contact every distro every single time there is a vulnerability.
there are very good reasons disclosure works this way, backed by a couple of decades of debate about it.
how many times it has to be said that it is impossible for linux kernel to communicate with anything but a minuscule portion of its downstream and _that_ has been done?
Who cares about how you are seen when you are selling 0day for big bucks? The bad actor makes more money than the 'legitimate' one without breaking any law. Punishing someone who didn't alert distros despite a patch being available encourages the company to simply find flaws and sell them for profit - it pays more to begin with.
If they want to take advantage of disclosure for marketing, they're either going to need to accept the norms around responsible disclosure, or they're going to need to accept how shirking those norms will come off. That's life in society. Sometimes it's annoying and sometimes it doesn't feel rational, but these norms have been negotiated throughout the history of our industry and are the way they are for reasons good and bad.
I just don't see the point in complaining about how shirking the norms of your industry will make you look irresponsible. I don't really care that they could have decided to sell the vulnerability instead. It isn't material.
It is absolutely not true that viable commercial vulnerability labs need to "accept the norms around responsible disclosure". There are no such norms. "Responsible disclosure" is an Orwellian term cooked up between @Stake and Microsoft and other large vendors to coerce researchers into synchronizing with vendor release schedules. It was fantastically successful at that, and it's worth pushing back on at every opportunity.
Tavis Ormandy dropped Zenbleed right onto Twitter. He's doing fine. You can blacklist him if you want; I imagine he's not going to notice.
Microsoft's policy is: "if you contact us with a vulnerability, you automatically agree to the terms of our responsible disclosure policy", which includes waiting 30 days after patch was created, and says nothing about how long that process takes.
There is actually no way to give them a friendly heads up, and then do your own thing. The only way not to be bound is by not sending them any notification at all...
You can email without agreeing to anything. But for a serious issue Microsoft would obviously try and track down who you are and what jurisdiction you are in.
> The Microsoft Bug Bounty Programs Terms and Conditions ("Terms") cover your participation in the Microsoft Bug Bounty Program (the "Program"). These Terms are between you and Microsoft Corporation ("Microsoft," "us" or "we"). By submitting any vulnerabilities to Microsoft or otherwise participating in the Program in any manner, you accept these Terms.
Those norms do not exist. Those are people asking companies to do stuff to benefit the person complaining for free, and many companies will not do that.
It seems to me you're unaware of them, but there are strong norms around disclosure. They've been discussed for decades. It is the expectation that vendors would be notified in a scenario like this.
No, there are users who want those to be norms. Qualified researchers happily sell substantive vulns to people who pay (Governments/Cellebrite and companies like that) enough to quell any complaint.
Which is again, irrelevant to the question of how disclosure works and what expectations there are around it because that is not disclosure and is not what was being discussed.
How does someone being incentivized to sell a vulnerability to a private organization over disclosing it publicly preserve a "high trust society"? Do you mean in the context of a "deceptively high-trust society"?
Those private actors aren't planning to sit around and hold onto these exploits they've horded forevermore, they're obviously paying for them so they can one day use them.
Unfortunately this is correct. As a security researcher I set millions in profit on fire for reporting vulns to projects that offer no bounties vs selling to highest bidder. I keep doing it because it is the right thing to do, but I would not blame someone that needs to feed their family making a different choice.
We must get public funds to reward ethical disclosure of big impact vulns like this.
Harder and harder to get good policy like what you describe when tech-adjacent people loudly argue for criminal penalties for anything other than coordinated disclosure :(
Are you claiming that if I sell 0day through a broker to the national Government of a given jurisdictions that the national Government of that jurisdiction is going to criminally penalize me?
If so, that's a bit naive. In the actual world, that buyer wants to buy more stuff from me, not penalize me.
I'm pretty sure they have a legal obligation in most jurisdictions not to sell 0days for profit.
And they absolutely have a moral obligation to do things in a way to minimize damage and impact to other people's systems. (I'm not saying "responsible disclosure" is the correct way to do that, but hoarding vulnerabilities and exploits and selling them to the highest bidder certainly isn't.)
It is categorically false that there's a legal obligation not to sell vulnerabilities. There's an obligation not to knowingly sell them directly to ongoing criminal enterprises. That's it. Plenty of people make fuckloads of money selling vulnerabilities for exploitation rather than repair.
(The buyers are the NSA, the IDF, Cellebrite, NSO and its successor corporation and that kind of thing. Depends on what you are offering)
You'll learn who the buyers are if you routinely have the really good stuff to sell! If you are offering iOS zero click on a semi-regular basis, the buyer is going to want to try to deal with you directly and preferably offer you a more regular form of employment, if you are interested. Some national governments may offer certain benefits to you, depending on your situation.
All depends on what you have to offer. If you were able to offer this https://arstechnica.com/security/2025/09/microsofts-entra-id... or something of that magnitude, a lot of problems in your life would just go away. The buyers would all be Five Eyes and the intelligence gain of having that kind of access even briefly is priceless.
In a more Western-centric context, imagine if you had a flaw like that, same 'no logs are generated' and 'every single customer account is accessible' but the impacted vendor was Alibaba Cloud. The researcher would get to name their price. That's the real world, that's the world we share. We shouldn't be blind to that.
> Researchers are under no obligation to engage in coordinated disclosure and are free to sell 0day for profit.
Uh... no? If you mean legally, some people might, depending on jurisdiction. But also, ethically? yes, researchers are ethically obligated to disclose responsibly.
> Just fyi.
...
> Be glad it was disclosed at all. Be glad a patch was available prior to release.
I am glad that a patch was available. Equally I can be glad that the linux community is strong enough to respond quickly, while also being angry that this person behaves unethically.
Likewise, when people in my industry behave poorly, or unethically; I'm now the person ethically obligated to both point it out, and condemn it. Not to become an apologist demanding I should be happy watching bad things happen, when much of the fallout could have been prevented with a bit less incompetence and ignorance.
> Researchers are under no obligation to engage in coordinated disclosure and are free to sell 0day for profit. Just fyi. Be glad it was disclosed at all.
I'm so glad these so called "researchers" aren't totally evil, I'm so grateful they're only half evil, give them a lollipop.
Whatever, the way they disclosed it isn't much different from no disclosure at all - the exploit would have been identified in the wild and fixed soon thereafter.
the way the disclosed it is the industry standard. think of the biggest security research teams you know (e.g. google), and they follow the same process.
non-security people always seem to get up in arms about it, but there is very good reasons why the industry has landed on the process it has, which has been hashed out over a few decades.
1. Status quo. Researchers are free to disclose to a vendor, free to sell vulns to legitimate companies, free to do full disclosure if they want. This situation benefits security. Researchers are able to pay their bills while also doing meaningful research into OSS projects that are unable to fund the kind of security audit they need. Harm reduction, of sorts.
2. Everyone is a bad actor. No one is going to do this work for free/for a bounty. Horrible flaws will be found and shared with ransomware gangs and the like. 0day will sell for a percentage of the ransom winnings. Researchers will live like kings, everyone else will suffer.
They should have a legal obligation to engage in coordinated/responsible disclosure, and it should be a crime to sell or disclose a 0day to anyone other than a state-designated security organization or the vendor/provider.
If it won’t be handled through criminal law then it’ll be handled through civil litigation: Anyone who was exploited as a result of this disclosure should sue the discloser for contributing to the damage they’ve suffered.
To be clear, the vulnerability existed in Linux, not in Xint Code. It existed whether this group disclosed it or not. Knowledge of it and exploits may have already been bought and sold among various groups with various motives including crime, terrorism, or cyberwarfare who likely made good money off it if this happened.
In that world, the vulnerability has more value to those who seek to exploit it for their own motives, regardless of the consequences. They hope that no one else stumbles on it and fixes it, preventing them from continuing to use it to do bad things.
In the world where it is disclosed, there is more value in fixing the vulnerability as the maintainer’s reputation is at risk (and potentially monetary loss or legal liability if they are shown to be negligent).
There is no such thing as "the responsible disclosure protocol". There's really no such thing as "responsible disclosure" at all, but "the responsible disclosure protocol" is a term I have literally never heard before. (I've been a vulnerability researcher since the mid-1990s, for what it's worth.)
> In computer security, coordinated vulnerability disclosure (CVD, sometimes known as responsible disclosure)
I guess you can learn something new after 36 years.
If you are referring to what you quoted, your pedantry and sharpshooting would result in an incomplete English sentence: "that's why we have the responsible disclosure" is missing a noun. Now that we are firmly in worthless pedantry:
Protocol (n):
1.a. a system of rules that explain the correct conduct and procedures to be followed in formal situations
1.b. a set of conventions governing the treatment and especially the formatting of data in an electronic communications system
If you don't like what I said or disagree, poke holes in factual inaccuracies. However, in the reality that I am pretty sure we all share, responsible disclosure is a well established protocol that is followed by many security researchers, and was imperfectly followed here.
As a user and admin I disagree. Makes one appreciate what a masterful bit of lexical-engineering “Responsible” Disclosure is, kinda like “Secure” (from me, not forme) Boot — “Responsible” Disclosure is 100% about reputation-management for the various corporation/foundation middleman entities sitting between me and my computer.
Those groups don't care that my individual computer is vulnerable but about nobody being able to say “RHEL is vulnerable” or “Ubuntu is vulnerable”. The vulnerability exists for me either way, and I'd rather have the chance to know about it and minimize risk than to be surprised by the fix and hope nothing bad happened in that meantime.
Immediate public disclosure is the only choice that isn't irresponsible as far as I'm concerned.
So if I found a vulnerability that lets hackers withdraw withdraw all the money in your account without a trail on where the money went, you'd be fine with them disclosing it to the public at the same time as the bank learns about it?
Even when there is no known use case of the attack (other than the security researcher's)?
> The vulnerability exists for me either way, and I'd rather have the chance to know about it and minimize risk
By the time you hear about it, the money could be gone because 1000 hackers heard about it from the researcher before you did.
> than to be surprised by the fix and hope nothing bad happened in that meantime.
Seeing your other (rightfully flagged) reply I want to tell you as a neutral party that yes this is missing the point of the analogy. You're basically saying "I would simply hit the brakes on the trolley". It's not that they're so hubristic they think it's impossible to legitimately disagree with their argument, it's that mentioning insurance is sidestepping their argument entirely. You're not addressing the general idea of getting hacked and suffering the consequences of the hack.
that is basically how all large companies behave anyway. socialize the losses (bailouts, layoffs, negative economic impacts in the communities they reside, etc.) and privatize the gains.
Why do you assume banks would keep on doing the same old thing but paying more because of it? The cost would make them learn not to design systems where something like this hypothetical scenario was possible.
You're missing the point (not sure if you're just being dense on purpose...). If you're bank would just return the money then its not a good analogy. If someone gains root access to your machine, presumably they can do damage that can't be undone. In other words, to continue the bank analogy, they would take all your money and you would have no way of getting it back. Presumably, you would not be ok with this. And even if, for some weird reason, you were ok with that, 99.9% of all other people would not be ok with it.
Respectfully, I don't think they're missing the point. Banking, as an institution, has its flaws, but deposit insurance isn't one of them. These vulnerabilities exist whether or not they follow specific disclosure rituals, and systems should be deployed with defense-in-depth so that one privilege-escalation flaw is a recoverable event. Inventing tortured counterfactual analogies doesn't change the basic thrust of the poster's point: the account is insured, so getting drained by an attacker is not a fatal problem. Of course people should still take steps to prevent that from happening, but that doesn't mean prevention is (or should be) the only cure.
My point specifically is that some damage isn't recoverable if there's a vulnerability that gives someone root access. This makes the bank analogy inadequate in the first place. Im not trying to argue about whether deposit insurance is good or bad. Saying they would get the money back assumes the damage done to ones machine would be recoverable, which may not be the case.
My understanding is that FDIC deposit insurance only protects against bank failure, not fraudulent activity. Getting your account drained by an attacker may or may not be covered by a patchwork of other laws at various levels, and you could very well end up shit out of luck.
> Immediate public disclosure is the only choice that isn't irresponsible as far as I'm concerned.
No, it's really not.
High severity vulnerabilities are responsibly handled by quietly neutralising them with subtle patches that do not reveal the vulnerability, waiting for those patches to distribute. Then patching or removing the root cause of the vulnerability (at which point opportunists will start to notice), and finally publicly disclosing it when there are already good mitigations in place.
Example: spectre/meltdowm mitigations.
I've been asked to use this approach myself when reaching out to maintainers. Sometimes it's possible to directly fix the vulnerability as a "side effect" by making a legitimate adjacent change.
With immediate disclosure the provider can decide to shut down while it is fixed. Or to notify users and make it their decision. Or to be prepared with a diversified infra and switch over to a non-vulnerable path. e.g, BSDs are not affected by CopyFail
The disclosure doesn't appear very "full". Looks like this was slipped into mainline linux among dozens of other mostly-irrelevant "CVEs" with nobody highlighting the fact that it is in fact dirty-cow-on-steroids.
Or is everyone expected to upgrade and reboot every 48 hours for all eternity and just deal with potential regressions all the time?
I think this reflects poorly on the original reporters. If you have a weaponized 700-byte universal local root exploit script ready to go, perhaps you should coordinate with major distros for patches to be available before unleashing it on the world. No matter how "veteran" you are.
I think I must misunderstand. Are you saying that you upgrade and reboot every production system that you administer to apply each commit to the kernel (branch it's using) essentially immediately?
That doesn't make sense to me for a few reasons, but I struggle to find a different reading that applies "upgrade and reboot on a moment's notice" to the "slipped into mainline linux" scenario. Kindly help me to do so.
No: your posture with respect to having to cycle servers is a super complicated subject and you address it both with process and with architecture (for instance: you can be blasé about things like CopyFail if you don't allow multitenant shared-kernel in your design in the first place). But no matter what process and design you have, if you're hosting sensitive workloads, you always have to be in a position where you can metabolize having to cycle your servers.
It's a category error to talk about a disclosure event like this as something that would destabilize someone's fleet operations. The Linux kernel is fallible. So is the x64 architecture. You already have to be ready to lock things down and reboot (or mitigate) at a moment's notice.
Remember: whatever else grumpy sysadmins have to say about this, Xint are the good guys. Contrast them with the bad guys, who have vulnerabilities just as bad as CopyFail, but aren't disclosing them at all --- you only find out about them when it's discovered they're actively be exploited. There's no patch at all. There isn't even a characterization of how they work, so that you could quickly see what to seccomp. That's the actual threat environment serious Linux shops operate in.
I find it curious to call someone dropping a weaponized root exploit before major distros or even LTS kernel git branches have patches ready "good guys". This could have been handled with much more grace.
To be fair, once Xint gave the heads up and the kernel team committed a patch, what was Xint supposed to do? Keep asking the kernel security team to backport patches for the LTS kernels?
As soon as a patch is committed, the clock starts ticking, the exploit will be discovered by reverse engineering recent commits. The commit was made on April 1st, Xint disclosed it on the 29th. If the Kernel Security team had wanted to, they had 28 days to backport patches in the LTS branches...
Again: I made the actual distinction between bad guys and good guys clear. Good guys don't become bad guys simply because kernel security is an inconvenience to you.
There are more than just good guys and bad guys; in particular, there are also opportunists.
Opportunists are the ones who will sell a 0day to bad guys. Or who will drop a 0day publicly to promote their services. And they’ll fight tooth and nail against any actual legal obligation to engage in responsible and coordinated disclosure, because they make more money without that.
It was clear that the original comment didn't say that, since we can see it right above. It was clear to me that the GP was using quotes as a way to use direct speech, not to imply that the GP literally said those words.
Those groups care about whether millions of computers are vulnerable, likely including your computer. If "immediate public disclosure" was done in all cases every vuln would be exploited and patches would be much lower quality. Shortening the disclosure timeline might be a good idea, 90 days is starting to feel long.
Being vulnerable is not the important part.
They have been vulnerable for years.
The problem is the probability of being exploited.
If everyone knows about the exploit details before a proper patch is available the number of exploited systems will skyrocket
Without taking a position on the disclosure mechanics: any hosting provider hacked with this was already playing to lose. It is not OK to run competing untrusted tenant workloads under a single shared kernel. Kernel LPEs are not rare. This was a particularly simple and portable one, but the underlying raw capability is a CNE commodity.
The Linux kernel is not usable as a security boundary, so anyone who wants to do "shared hosting" and not be hacked needs to use something else, like gVisor or firecracker VMs
The only important system that uses it as a security boundary is Android and there is mitigated by the fact that APKs need user approval, plus strict SELinux and seccomp policy plus the GrapheneOS hardening, and in this case the mitigations succeeded (https://discuss.grapheneos.org/d/35110-grapheneos-is-protect...)
I thought that was the entire design goal of the Unix model, didn't it originate in the times when hundreds of users logged on to a shared mainframe? There are still public Unix servers like SDF out there. SELinux is just an extra layer so that if someone gets root (ex. due to an exploit in your setuid code or cron jobs etc) it's not game over.
I'm quite sure there are many application hosting providers which rely on container runtime such as runC (default runtime of containerd/Docker), and a shared kernel between users.
In a just world, those companies would be held legally accountable for negligent practices. The Linux kernel upstream has made it clear for decades that security is a dirty word.
Expecting people to do the right thing is a fundamental issue here. Why would you ever expect for all of vulnerabilities to be disclosed privately? There's very little actual incentive to do this.
I'm honestly unaware of what systems could be put in place to prevent this but expecting people to always do the right thing is fantasy level thinking. I mean I bet the disclosers thought they were doing the right thing, hence why it's a bad thing to rely on.
The worst thing would be to exploit or sell it for profit. Instead of that, publicizing the exploit is closer to neutral–good in my books, that did trigger a really quick reaction from the different actors to patch their kernels and systems
Imagine how much quicker the distros would have reacted if they were given a heads up a month ago. But, sure, I guess kudos to this company for not being actively criminal, and merely bumblingly incompetent and overly eager to get their marketing pitch out the door.
Why don't all these distro maintainers add their own back doors, and mine crypto off our machines without our knowledge? Surely, there is some legal fine print they can add that would let them do that. There is very little incentive for them to maintain these systems, given how thankless and underpaid the work is.
Greg and Linus do not believe in the entire concept of "vulnerabilities" in the Linux kernel and do not believe in the methods that distros use like cherry picking, therefor they typically are against issuing CVEs, scoring CVEs, describing vulnerabilities at all (if you use the word "vulnerability", your patch will be rejected), etc.
It's fundamentally their position to not work the way that you describe.
What is your interpretation of why Greg KH released a version of 6.12 with this fix in it today, other than to help distributions avoid this vulnerability?
Partly they already have enough on their plate. It's up to the reporter to pick how to handle the disclosure, and unless a specific maintainer chooses to handle it, the Linux security team clearly says they won't.
Partly they have a strong belief that all kernel bugs are vulnerabilities and all vulnerabilities are just bugs; sometimes taken to the extreme in both ways (on one hand this case where the vulnerability is almost ignored; on the other hand, I saw cases where a VM panic that could be triggered only by a misbehaving host—which could just choose to stop executing the VM—was given a CVE).
This couldn't be more backwards. This has literally nothing to do with bandwidth. The kernel is a CNA, they are explicitly the ones to do this.
The reason they don't is because Linus and Greg have repeatedly, publicly stated that they don't want to because they don't believe that vulnerabilities conceptually make sense for the linux kernel and they refuse to engage in the process.
> they don't believe that vulnerabilities conceptually make sense
That's exactly what I wrote: "they have a strong belief that all kernel bugs are vulnerabilities and all vulnerabilities are just bugs; sometimes taken to the extreme in both ways".
But there is also a question of bandwidth. If a maintainer asks to bring a specific vulnerability to distros-list, the kernel security people will be reasonable. I did it last March.
Seems a little crazy. Somebody should evaluate blast radius and do appropriate distro notifications in a case like this (I presume the impact was part of the disclosure, so not much extra work).
You know the linux kernel is a free software project right? If you think “somebody should” do a thing but you aren’t prepared to do it yourself then you should maybe ask for a full refund.
U/Deb/RHEL are 'upstream' of a lot of other projects, and fixes would trickle down to Rocky, Alma, etc. Perhaps VM OS in cloud (AWS, Azure) could be a usage gauge as well.
The patch was available. Upstream just doesn't communicate vulnerabilities because they have a personal dispute with distros about how to handle patching.
If it's not a crime I see no reason not to work with partner nations to build responsible disclosure into a legal framework everywhere because it pretty obviously should be.
This is kind of a thing already in the EU. Under NIS 2, vulnerabilities should be notified to a CSIRT as well as upstream, and the CSIRT shall identify downstream vendors and negotiate a disclosure timeline. I don't know whether they're any good at it or not, though.
You know companies are allowed to pay people to find vulns, and pay people bug bounties?
Instead of that, you’d rather make the law compel free individuals to limit their speech, or to hand over their work to big companies privately, so big companies can save money?
That doesn’t sound like a nice future, if it’s even enforceable at all.
That's besides the point. If people use the official mitigation on https://copy.fail/#mitigation they will not sufficiently protect themselves on mainstream distros like Ubuntu and Debian.
The page also states
> Most major distributions are shipping the fix now.
This text was probably prepared in advance, but this was simply not true at the time of publication.
Basic care would involve making sure the patches had made it into the wild before ending the embargo, and nagging the relevant parties if not.
Edit: As of this writing, most distros including Redhat, Fedora, Debian Stable, do not have patches available in the package repos, though they're being actively worked on.
Not true, if there’s any evidence of the exploit being used in the wild, it’s much more responsible to release immediately.
Considering that the patches have been available for a while, someone surely reversed what they were for and was actually exploiting this in the wild.
In the age of AI, I’d argue that “responsible disclosure” is dead. Arguably even in closed source projects. Just ask Claude to do a diff between the previous version and to see whether anything fixed in there could have had security implications.
We’re not there yet, but very soon the only way to responsibly disclose a vulnerability will be immediately.
But they didn't release immediately -- they waited a month, but forgot to tell the distros, and forgot to check if waiting a month had actually lead to distros picking up the patches and shipping them.
Which just reinforces my point. The patch was available, therefore, where the exploit lies was also available.
Linux kernel is one of the most audited open-source projects ever. I guarantee you that someone did reverse the patch.
> but forgot to tell the distros
Probably an oversight, but irrelevant. The bug was in the linux kernel. It's insane to suggest that they should have notified everyone shipping the linux kernel.
Patches are still in the process of landing in most major distros as of the time of this writing. Most users are not able to get an update through their distro's packaging mechanisms.
It's a local vulnerability at least. How many people do you let log in to your router?
With the way linux is used these days, I'd guess the number of systems with untrusted local users is pretty limited. Even with shared hosting, you generally have root in your VM or container anyway. Unless this enables an escape from that?
Still the risk that people who run "curl | bash" without care could get bitten, but usually its "curl | sudo bash" anyway...
> Even with shared hosting, you generally have root in your VM or container
Lots of shared hosters don't use VMs or containers. It's some arbitrary number of people logging in to a shared system, each one with a home directory under /home/THE_USER_NAME. i've had several such hosters over the years (thankfully not right now, though).
> With the way linux is used these days, I'd guess the number of systems with untrusted local users is pretty limited
Things like HPC clusters are multiuser & don't entirely trust their users. If they did we wouldn't need users/groups/permissions etc in the first place.
Yes. Not even just HPC clusters, shared login servers are pretty common in academia. I manage several in our lab. Sure, we mostly trust the users against malice more or less but not so much against incompetence. A malicious vscode plugin would run rampant in this space.
And then there are users running claude-cli and friends who may just find it convenient to use a local root exploit to remove obstacles.
I think it’s reasonable to expect folks in the security community who go to the trouble of creating a website detailing security vulnerabilities in specific listed software to pre-notify the security teams of that software. The CopyFail website calls out Ubuntu and Red Hat specifically, but apparently the author of the site did not inform them of the issue?
But even if you think making unethical decisions in personal self interest is something no one should be criticized for, surely the Linux kernel team ought to have some process for notifying the top distributions of an upcoming LPE, just out of practicality.
In what sense do you believe that the reporter did not notify the security team of the relevant software? The vulnerability is in the kernel. Reporter responsibly disclosed using the kernel’s security report mechanism and waited until a patch was ready.
Distros are downstream of kernel, that doesn’t entitle them to expect to be contacted directly by every security reporter. That’s not on them. Distros that are big enough should be plugged into the linux security team for notifications.
Security researchers cannot be held responsible for broken lines of communication within the org charts of projects that they study. They’re providing a valuable public service already, how much more do you want?
It is suggested that they out of an abundance of caution and 5 or 6 emails. If this is entirely to much to expect we can always help them by mandating that they spend 6 figures annually meeting a much more robust set of requirements that will include notifying all possible affected parties down to Hannah Montana Linux devs if any still exist.
Any strategy that assumes that the rest of the world is functional or makes you personally responsible for fixing all of it is equally broken but there is a reasonable middle ground and sending a few more emails lies within it
> we can always help them by mandating that they spend 6 figures
Who’s we? Mandate with what authority?
AWS and GCP are downstream another level. Should the reporter also have worked with them? And their customers? And the customers of their customers?
IMO this whole discussion seems like people are annoyed by the security researchers doing god’s work and wish they didn’t exist or think that they should be fully subservient to the projects and companies they are helping for free. The bugs were there before the researchers revealed them!!
The notification happen when the fix was shipped. That people would prefer to been spoon fed only serious security issues is understandable, but not realistic.
A large percentage of kernel fixes have the potential to be similarly bad. For some the potential isn't even realized until after the fix has shipped.
Ever stable release GregKH says you must upgrade now, because there is something security relevant in there. This happens at least once a week.
As for shared hosting providers it is my sense that there is always at least one local privilege escalation available to miscreants. Making shared hosting only safe if there is a certain amount of trust.
I remember bugs that were similarly bad from my university days 30+ years ago. Has anything substantially changed?
> Who knows how many shared hosting providers were hacked with this.
I'd consider a shared hoster which allows users to run their own (native) code and doesn't use VMs for tenant isolation extremely irresponsible in 2026.
This is probably more common than you think. VMs are expensive, both in resources and cost (if you’re using something commercial). OS-level isolation (shared kernel, cgroups, namespaces) is used pervasively
Argument from uncertainty is not a good way to reason about this.
I could equally ask: "Who knows how many attackers learned about this vulnerability from this disclosure, and used it before the distributions fixed it?"
Yes, you could. Thats the core of my point: there is no Right way to handle vulnerability disclosure. There are many competing factors, most of them have major elements of uncertainty because you can’t know who knows what or how various projects or stakeholders will react.
So maybe folks should take a break from the kind of armchair quarterbacking that this was “incredibly irresponsible”, as was done upthread, or that the researchers should be blacklisted for life, as a parallel commenter stated.
and its your opinion that it doesn't. Shall we continue stating the obvious? We are communicating using glyphs. This language is English. We are on Hacker News. This branch of the conversation is extremely unproductive.
I asked a question and you replied with a statement. Your statement didn’t frame itself as an opinion but as fact.
The hilarious bit is that the idea that they needed to coordinate is clearly broken even in just this example. They did give prior notice to the Linux developers, who issued a patch. And they’re still getting raked over the coals in this comment page by armchair quarterbacks who have decided they needed to coordinate with specific distros. If they’d coordinated with those distros, somebody would have a pet distro that didn’t make the cut and they’d be pissed about that.
There are risks no matter how they do it, and there will be people who are pissed no matter how they do it. Security researchers don’t owe anybody a specific methodology.
you seemed to suggest with your initial statement that any disclosure was acceptable as people would have been using the exploit prior to the disclosure. I don't think that's a strong argument given now the initial people who were using the exploit prior to disclosure are now joined by people who have learned of the exploit as a consequence of the disclosure happening before all the distribtions were ready.
So I feel like the argument reduces into "why is it a problem that now anyone could exploit it, if some people were exploiting it already". Which imho isn't a sensible argument because the issue is clearly the amount of people capable of using the exploit for nefarious purposes, which has increased.
Idk why you felt the need to use quotes to wrap something I didn’t say, and that is a pretty uncharitable attempt at reframing my question. If you wanted a quote, here’s what I’d say:
“Because we can’t know if there was exploitation by existing parties who had discovered the vulnerability on their own, there are upsides to disclosing earlier so that affected users can take mitigating steps and review their systems for indicators of compromise. Additionally, the more projects the researchers pull into the loop for coordinated disclosure, the higher the likelihood that they further leak the vulnerability to more attackers.”
Idk why you felt the need to use quotes to wrap something I didn’t say. Despite the fact I didn't say that, its a much more interesting argument than your original statement implies and it is unfortunate we didn't start there.
However the issue is that we cannot know if the attack space has been broadened or lessened as a consequence of this disclosure, because of how eager it was. If it wasn't eager then we could much more comfortable in suggesting that the attack space has probably been reduced.
Given the exploit had been living in the linux code base undetected for so long in the first place, I think its fair to state that disclosing the exploit prior to the distributions being ready and given the distributions are the principal attack vector of the exploit: that the researcher has made the situation worse and should reflect on their actions.
… I used quotes to wrap something that I was saying. I even called out that it was something I was saying, as a more accurate variant of what you’d claimed I meant.
and I prefaced my quotes with the statement "So I feel like the argument reduces into". I mean, idk what punctuation I'm supposed to use there that doesn't offend you, but I just figured we can all read words and it was clear that I wasn't saying you said that, but rather, as I read the argument it was reducable to that and I took issue with that potential reduction.
The idea about the available exploit space and how the actors within it might, or might not move is a much more interesting avenue of conversation and I thank you for elaborating on your initial comment. <3
I do however feel that its hard to be confident about whether or not the attack space has been increased or reduced as a consequence of the eager disclosure. I feel we could make the case either way.
You could try to make that case either way, but as has been pointed out by others all over this thread, the system we've landed on (90/+30) is industry standard after over two and a half decades of experimentation.
Anything else inevitably has worse for the public good.
Having spent that entire time and then some on both offensive and defensive teams, I assure you longer delays after notification do NOT decrease the overall risk to the public.
There's a reason we've landed where we have as a security community.
The disclosure is private. Meaning neither the commit messages nor any public info can leak too much information about the bug. It's usually kept rather discrete.
It is impractical for the kernel to broadcast to all its users privately.
Meaning that either a) distro maintainers should be privy to it, but where does this end?[1] or b) we have the current situation
[1] probably the top 5 distros security teams can just be copied into the private mail. Maybe the kernel security private list can forward the emails to them as well.
Problem is, every other type of communication between distros and kernel is implicit. In commit messages, patches and release notes. So it's an exceptional case.
BTW, with LLMs there's a new issue. It is now cheap to scan the kernel commit log maybe in _next and ask it to identify what could be a patch for a private disclosure. And then immediately RE the patch and exploit it on deployed kernels.
> Who knows how many shared hosting providers were hacked with this.
None? Because nobody* does hosting using Linux users as a security boundary. It's not the 90s.
* Standard HN disclaimer for people that think that some retro shell box with 10 users disproves "nobody": nobody does not literally mean exactly 0 people in this context.
> Anyway, this is a disaster. It was extremely irresponsible to share the exploit with the world before the distributions shipped the fix. Who knows how many shared hosting providers were hacked with this.
Maybe it is irresponsible how little attention we pay to software security. Maybe, software developers of all kind should spend an entire year not developing any features at all, but fix all the tech debt of 30 years instead.
Yes, that sounds revolutionary, but I do not see an alternative in an age where all you need to find kernel bugs of this scale with AI agents.
> It was extremely irresponsible to share the exploit with the world before the distributions shipped the fix.
It's a total arsehole'y move to not share with open-source projects (like Debian) but for commercial vendors like Microsoft I don't give a crap.
Now let's not get carried away either: that's a privilege escalation, so it already requires access to a local account. We're not exactly in Jia Tan "I backdoor every SSH out there if your Linux distro is using systemd" territory either.
> It was extremely irresponsible to share the exploit with the world before the distributions shipped the fix.
Yes, this was clearly a marketing stunt to promote Xint code.
I, for one, will never use Xint code and will advise everyone to never use it. To anyone working there: enjoy your 15 minutes, I hope this backfires right in your face.
External security research happens for one of only a few reasons typically:
1) hobbyists who are learning or just like to do it for fun
2) bug bounties (good luck with those in most open source)
3) marketing for security companies
4) non-public research going to CNO/CNE
If you want to kill 3, the output of 1 will not come close to 4 and the public is NOT better off with fewer public bugs.
It does? The disclosure even says the concern for single user systems is very low. If someone has access to your single user system, remote or otherwise, you’ve already lost on the sort of device people would be switching from windows to Linux on.
> The disclosure even says the concern for single user systems is very low.
For single user systems (not rigorously defined, I presume it's the intersection of our two definitions which we might be talking about) the nature of the exploit is local privilege escalation, of which there could be many possible, and many mitigations / countermeasures against. This could have suddenly appeared from the ether of "unknown unknowns" for some people.
Those people farther up the food chain still potentially have service accounts, maybe even user accounts for some purposes, perhaps "trusted" services which deliver them code which they deserialize and run once. (Have a pickle.)
severity * impact * likelihood
Not everyone looking to migrate from Windows 95 plans to run everything as root afterward.
> Note that for Linux kernel vulnerabilities, unless the reporter chooses
to bring it to the linux-distros ML, there is no heads-up to
distributions.
Why would they imply it is incumbent on the reporter to liaise with distributions? That seems to assume a high level of familiarity with the linux project. Vulnerability reporters shouldn’t be responsible for directly working with every downstream consumer of the linux kernel, what’s the limiting principal there? Should the reporter also be directly talking to all device manufacturers that use Linux on their machines?
IMO reporter did more than enough by responsibly disclosing it to linux and waiting for a patch to land.
Aren’t there people in the linux project itself with authority over and responsibility for security vulnerabilities? One would think they would be the ones notifying downstream distros…
```As such, the kernel security team strongly recommends that as a reporter of a potential security issue you DO NOT contact the “linux-distros” mailing list UNTIL a fix is accepted by the affected code’s maintainers and you have read the distros wiki page above and you fully understand the requirements that contacting “linux-distros” will impose on you and the kernel community. ```
Do I expect that every distribution is already patched? I don't. However each of us choose the distribution to run. Security can be one of the criteria for the choice. I played safe and I'm using Debian. Other people can make a different tradeoff maybe based on their personal threat analysis.
There are people running end of life kernels and distributions in production, or with pinned old kernels especially on ARM SBCs. I know both. Those are other choices made at the user end of the process.
IMHO the disclosure and fix process was run in the proper way from the researcher to the end user.
The kernel team has been at odds with the CVE process and the oss-security community about this stuff for many, many years now. It's a big part of why the kernel team established a CNA and started flooding CVE notifications; they don't believe that security problems are different than non-security problems, and refuse to establish norms or policies based on the idea that they are.
> […] they don't believe that security problems are different than non-security problems, and refuse to establish norms or policies based on the idea that they are.
They believe there is no difference being able to get root and not being able to get root? It seems to me that to-be(-root) and not-to-be(-root) are quite different.
No, they believe that almost all bugs in an operating system kernel are also likely to be security bugs. The ones which get domain names, POC exploits, and CVE assignments are the ones which were found by security researchers. But the bugs that get found and fixed by kernel developers regularly without fanfare are also very likely to be exploitable. It's just that nobody took the time to cook up an exploit chain. To kernel maintainers, it's silly to assign CVEs to just some of the likely exploitable bugs just because a security firm found them. So they decided to take the reigns and handle CVEs themselves, to ensure all potentially exploitable bugs are marked as such.
It's such a bizarre viewpoint. I wonder when Linus will see sense.
IMO it's pretty obviously not a view that they seriously hold, it's just one of those technical justifications people come up with to avoid admitting something they don't want to admit - in this case that Linux has a poor security track record.
I think it's an extension of the premise that you should just be taking the whole stable tree with all its patches constantly, whether they're labeled as security fixes or not, because you can never really know for sure some bugs weren't security bugs.
I don't agree with the premise, but I do think it's a sincerely held one.
The kernel begrudgingly admitted of the existence of LTS releases, they really don't like long-lived kernels and people not tracking at or near the latest release.
I dunno, if you think about it for more than a few seconds you can see the obvious holes in it, like it's definitely true that some bugs are "may allow RCE", but you also can do a LOT better than not even trying. And even if you do say "we're not putting the effort in to backport security fixes" (which is fine), that doesn't entail "security bugs are just bugs".
These are smart people. If it wasn't about their own project I really think they'd have a different point of view. I wonder what they say about Microsoft's security bugs for example!
Literally never. Why would he? He's surrounded by sycophants. And we have Greg for whenever Linus isn't involved anymore, and Greg is just as boneheaded.
The reporter took time to check and mention on their website specific distributions Ubuntu/RHEL/SUSE. One would have thought reporting to security teams of at least those would be responsible.
If you can't write it down, why would you expect it to be universal and enforceable? Different cultures exist and have different opinions on what "decency' means, after all.
A security researcher's ethical obligations are to protect users over vendors (barring any contractual agreement in place). From what has been discussed in this thread, they meet that bar.
Sure, they could have gone the extra mile to ensure the distros were in a good place to patch before they published the exploit. That's a kindness you can wish for, but don't disparage them for not going that extra mile. It's a bonus.
It's also possible that it simply didn't occur to them to do so this time. There's certainly lessons to be learned either way. I don't know that the right lessons will emerge from hostility.
> If you can't write it down, why would you expect it to be universal and enforceable?
and this is the problem. It used to be the case that if you were smart enough to find an exploit you were also smart enough to realise what would happen if you irresponsibly disclosed it. I guess these tools have made that pattern no longer apply.
From my point of view, they told the kernel security team which is in charge of fixing this. If it’s important for them to tell other people, then it should’ve been written down and further reiterated when they made their report.
The skills to detect code exploits is not the same as the skills to navigate an informal org chart to the satisfaction of an amorphous audience if end users (i.e. us on HN).
That said… as they are a company that supposedly specializes in this field, and is trying to sell a product, I do believe they should do better. Right now, I don’t have much confidence in their product.
Yes :) The blackhatter would obviously sit on it until they can sell it or use it, the whitehatter collaborate the kernel and distros to patch, and the greyhatter argues on HN whether the latest *fail was responsible enough or not.
The reporter made a website explicitly calling out Ubuntu, RedHat, Amazon, and SUSE but didn’t notify them, and you think that’s reasonable? That they might not have known those distributions are downstream from the kernel team?
yes, because 30 days had passed from the time the patch landed in the kernel, as per industry standard.
approximately every security researcher, including the likes of google and other big names you may know, does a 90+30 disclosure, which is what happened here. they do this for good reason, which has been figured out over decades of experience in reporting thousands and thousands of vulnerabilities.
the only security researchers i know of that dont like 90+30 actually argue for shorter timelines (or immediate disclosures).
What is the heuristic for who should get the heads up? Should they notify amazon but not google simply because they named amazon linux in the report? Seems to me the answer to my first question gets messy fast.
Mind explaining how sitting on it a month after the patch landed is 'faster'? To my mind, that's a month where attackers could analyze commit logs, but maintainers are not acting with urgency to ship fixes.
No, I wouldn't, because my own preferences are towards immediate disclosure. Tavis Ormandy dropped Zenbleed out of the sky onto us. It wasn't comfortable, it was a scramble for us, but I don't blame Tavis for it; he made a principled call. Better that people know, than that information be concealed from them while designated elites perform a process.
you are in another comment thread, of this very post, calling these reporters bumbling and incompetent for their disclosure. "merely bumblingly incompetent and overly eager to get their marketing pitch out the door" - that is your quote.
you also said "Basic care would involve making sure the patches had made it into the wild before ending the embargo", which is the literal opposite of immediate disclosure.
but now you are saying they should have just dropped it with no reporting at all? because that is what "immediate disclosure" means. pop up the exploit script on twitter and call it done.
Yes, if you release the vulnerability as soon as possible, that's a good choice. If you have an embargo and make sure that fixes get out to users in a timely manner before ending the embargo, that's also a reasonable choice.
If you're going wait a month between landing the patch (possibly notifying attackers), but not notify the people who may get the patch to users, it seems like something was mishandled.
> No, you're in more pain, but other defenders with different postures benefit from having faster and fuller disclosure.
Good for them. But just because some folks cannot afford 24/7 response teams and on-call personnel that doesn't make them or their systems any less important.
Lots of non-profits and academic institutions had to scramble because of the Linux kernel team's position of non-communication to distros.
The conversation about how Linux handle these things is a good and worthy one to have and one "non-profits and academic institutions" need to have when they select distributions. I'm just here to push any of that scrutiny off the vulnerability reporters; Linux is lucky to have them, even if it's mishandling their reports. Vulnerability researchers don't owe these people anything.
What's interesting is that their website is also down right now. These seem like special-timed DDos attacks so maintainers cannot communicate the issue well.
> Nope, sorry, we are NOT allowed to notify anyone about anything "ahead
of time" otherwise we will have to tell everyone about everything.
That's the only policy by which all the legal/governmental agencies
have agreed to allow us to operate in, so we are stuck with it.
Stop blaming the reporter. Start asking kernel to fix their process. Linux kernel is no longer a toy project, it has full time employees employed by various companies. They should have handled notifying distributions. Not some rando.
Look, if they namedrop specific distros in their announcement (marketing) blog post as affected, I think a heads-up before publishing that is appropriate and expected.
I don't think they would have gotten as much flame if it weren't for how the RHEL 14 mention and such were put.
This is a security company with a professional(?) communications department banking on pointing fingers at distro maintainers. We are not talking about solo security researchers or academics here.
Exactly. Any security person absolutely KNOWS that the distros are still going to be vulnerable. They're exploiting this process loophole to knowingly cause chaos and gain notoriety.
At this point this is not really white-hat/ethical hacking anymore.
Ofc the kernel-distro security loophole is stupid and should be patched ASAP, but that doesn't absolve this company of wrongdoing.
Linus should take his trademark autistic rage where he calls other peoples code "dogshit" onto his own work for once. He likes the glory of leading the kernel development but not the responsibilitys like this.
No, I will. The distros and the kernel devs should be talking and moving on high sev patches, sure. But real people will have gotten hurt because the reporter didn't want to wait for that to happen. That's on them.
It's one thing to report a vulnerability, another entirely to make a crazy exploit available for any tom, dick, and harry to take and use. It was irresponsible of whoever came up with it to release it in the world without first giving major distros a head's up.
Bashing on the reporter is pointless feel-good. This is a massive vuln. It was 4 weeks after Kernel had a patch. They had no way to know if others parties had also discovered the vuln. Lord Knows how many millions of systems could already have been rooted. The reporter is not their minion.
If I call 911 to report a fire at an oil storage facility - and they ask me to alert the hospital, then phone the neighboring county's Sheriff Dept., and then...yeah. Either I'm way out in the sticks (and known to/trusted by the 911 operator), or else the 911 service is run by children.
Just for what it's worth, I just pushed an eBPF-based workaround for people who are running kernels in which AF_ALG is linked directly into the kernel and not as a module: https://github.com/Dabbleam/CVE-2026-31431-mitigation
I am running this in production right now and it mitigates the attack, with no unexpected side-effects as far as I can see.
Interesting comment by Greg Kroah-Hartman when asked why the kernel team doesn't notify distros directly
> Nope, sorry, we are NOT allowed to notify anyone about anything "ahead
of time" otherwise we will have to tell everyone about everything.
That's the only policy by which all the legal/governmental agencies
have agreed to allow us to operate in, so we are stuck with it.
I'd be interested in knowing more about that policy... Seems that there should be exceptions for the major distros.
Of course, major distros who have contracts with SLA could also pay for someone to be on the kernel security team and get a heads up like that..
The members of the kernel security team are not allowed to tell their employers anything that happens on the security list. They are there as individual members, not as employees.
And try to define "major distros" in a way that actually means anything viable.
If you just want to count users, then that would only be Android (everything else is a rounding error.) After Android, that would be Yocto, and then Debian. All distros after that are mere fractions of overall users compared to those 3 by number of running systems alone.
If you want to count it as "$ spent on Linux" then that cuts out Android and Yocto and Debian as those distros are free, and would focus purely on the tiny installed base of paid Linux systems, and cut everyone else out.
So what is a fair way to do this other than "we notify no one, and tell everyone to always update their systems to the latest stable releases that we support."
Especially as there is no way for us to determine your use case (i.e. if a specific bug is a vulnerability for you or not.)
`nosuid` and probably `nodev` should IMO be the default filesystem mount options.
`/dev` is already a special devtmpfs and the initrd minimal /dev can just explicitly mount the initrd tmpfs rootfs with `dev` and `suid` if necessary.
Letting SUID binaries just "exist" anywhere is a stupendous security issue. What if you mount some external storage medium, how are you to verify that none of the SUID binaries on that block device are malicious.
Additionally, this exploit appears to only work if the user executing the SUID binary can also read the SUID binary. There's no reason for non-root users to have read on a SUID binary.
NixOS does this correctly. No SUID in the normal package installation directory `/nix/store` and no package leakage outside of that no `nosuid` can safety be used on all other mountpoints. The exception is just a single-purpose `/run/wrappers.$hash` directory that safety contains executable ONLY SUID wrappers.
While I hate suid as much as the next person, it's really not the problem here.
The bug that is being exploited gives you basically arbitrary page cache poisoning. At that point it's already game over. Patching a suid program is maybe the easiest way to get a root shell from that but far from the only.
The proof of concept exploit is just that. It is meant to demonstrate one attack vector only. There are many others. If your goal is to prevent the conceptual exploit only then there are many easier ways to accomplish that, such as blacklisting, that does not make you safer.
With this vulnerability you can manipulate the page cache. You could also manipulate ld.so to hook into arbitraty system calls, or set your uid to 0, or any of another dozen or so ways to elevate your privileges.
Mount points have nothing to do with this, even if is always a good idea to disallow suid in user writable areas and prevent reading suid files, but that's for other reasons. NixOS does nothing to fix this and is just as vulnerable as everyone else.
Without read permissions you cannot execute the binary, that would not make any sense.
To execute the binary it needs to be read from disk and loaded into memory.
In fact if you have read permissions but not executable permissions on a specific binary then you can still execute it by calling the linker directly /bin/ld.so.1 /path/to/binary (the linker will read and load the binary and then jump to the entry point without an exec() call)
Removing world-readability from all setuid-root binaries on the system would be sufficient to kill the PoC script provided for this vulnerability. It would not be sufficient to prevent exploitation though; there are many ways to abuse the ability to write to files you have read access to in order to gain root, for example by using the vulnerability to alter the cached copy of a file in /etc/sudoers.d/, or overwrite /etc/passwd, or /etc/crontab, ... the list goes on.
If they don't have world-execute permission, an access(2) check for executability would return negative, leading to things like shells not tab-completing it. The kernel would also deny attempting to execute it, as it is not executable for your fsuid.
This workaround only applies to kernels with the impacted code compiled as a module. RHEL, Fedora, and Gentoo (we use a modified Fedora config) all are configured to build this in directly. Without a patch or config change (as Sam from Gentoo was alluding to), those distributions remain vulnerable.
For compiled-in kernels you can also work around it without rebooting via apparmor, seccomp or SELinux at the least, there may be eBPF or other methods too.
That is true, but if at least the widely used ones would get notified before that would be beneficial. If they have a responsible security contact point.
Then the ones that aren't notified will complain. I think it's on the distros to follow kernel developments since they are consumers of the kernel, not the other way around. Kernel devs can't possibly know all of the users they need to notify.
they disclosed 30 days after the patch was merged in the thing they reported to.
its the same disclosure policy as google's project zero, and several other major players, so you should probably be trying to ping a lot more people
reporters should not be responsible for finding out and individually reporting to every downstream consumer. blame the kernel security team, who is in a much better position to coordinate notifications to individual distro security teams.
The security research community would run you out on a rail if you tried to take a successful research product and attach mandatory disclosure norms to it.
Not having the module loaded doesn't mean you're not vulnerable, the kernel loads the module on-demand when it's needed. I tried the exploit on such a system, and it worked.
However, not having the module loaded does mean that in normal operation you don't need the module, so the proposed mitigation of disabling the module is safe in the sense that it won't disrupt anything.
I don't know what exactly can load this module but the servers are running for many weeks and I suppose that if something will load this module, it stays loaded until the next reboot.. no ?
I tried to rmmod on all servers and rmmod always returns `ERROR: Module algif_aead is not currently loaded`, that's why I think it's fine. Of course I take a look on https://security-tracker.debian.org/tracker/CVE-2026-31431 for the updates.
For context, the author of the linked post, Sam James, is a Gentoo developer.
Anyway, this is a disaster. It was extremely irresponsible to share the exploit with the world before the distributions shipped the fix. Who knows how many shared hosting providers were hacked with this.
It's also worrying that it seems there's no communication between the kernel security team and distribution maintainers. One would hope that the former would notify the latter, but apparently it's the responsibility of whoever finds the vulnerability.
i have no problem with disclosing a vulnerability 30 days after its patched in the thing you reported to. (in fact, for those unaware, this is the same policy that google's project zero uses: "90+30" https://projectzero.google/vulnerability-disclosure-policy.h...)
the real problem is:
>It's also worrying that it seems there's no communication between the kernel security team and distribution maintainers.
the reporter should not be the one responsible for reporting separately to every single downstream of the thing they found a vuln in.
what should be happening, as you allude to, is a communication channel between the kernel security team and distribution maintainers. they are in a much better position to coordinate and communicate with the maintainers than random reporters are.
the minute the patch landed in the kernel, a notification should have gone out from the kernel team to a curated list of distro security folk that communicated the importance of the patch, and that the public disclosure would be in 30 days.
>the reporter should not be the one responsible for reporting separately to every single downstream of the thing they found a vuln in.
Not "separately to every single downstream", there is the "linux-distros" mailing list for disclosures: https://oss-security.openwall.org/wiki/mailing-lists/distros
This random blogpost from 2022 serves as a proof that disclosing kernel vulnerabilities to the distros list is a well-known practice: https://sam4k.com/a-dummys-guide-to-disclosing-linux-kernel-...
I agree it's a shame that the process isn't more streamlined and the kernel developers aren't forwarding the reports to the distros list.
It is literally not the vulnerability researcher's problem to solve or address this.
If you just want to get a bug fixed that annoys you, it's of course out of scope.
If researchers want to showcase their ability (either individually or as an organization) to identify and address security vulnerabilities in complex multi-stakeholder environments, I very much expect them to figure this out. After all, it doesn't make much sense if a company, after commissioning a security review, needs to hire a different firm to handle the vendor interactions, so that identified issues are resolved with minimal impact to the business.
> a company, after commissioning a security review, needs to hire a different firm to handle the vendor interactions
These vendor interactions you're referring to are the company's customers, correct? Are you proposing the company hire another company to manage getting updates to their customers?
Agree, but then where does the accountability lie? Presumably with the kernel maintainers themselves, correct? SOMEONE dropped the ball here. If we can't point the finger correctly, that seems like a problem in of itself.
It looks like the expected thing happened.
The kernel devs patched the kernel. The kernel devs have a pretty known, straightforward stance in how they ship fixes for anything, because anything in the kernel can be a security problem.
Distro maintainers can see kernel changes. Some distros aggressively track new changes. Others backport what they feel are relevant. Others don’t do either.
Users pick what distro they use, and how they set up their infra.
Maybe if I were paying for RHEL licenses I’d be eyeballing the money I pay and RHEL’s response time.
But the ownership here lies with system operators, who pick their infrastructure, who design their security model, and who build their operational workflows. This vuln is a great example: people who looked at shared untrusted workloads on a single kernel and said “Hell no” had a much calmer day than teams who thought that was a good idea.
The fact that you had to take a whole paragraph to explain the contortionist arrival at something that isn't even really super clear after you explained it (you kinda pointed the finger both at end users and at distro maintainers simultaneously) and essentially boils down to "well, you as the end user need to be following kernel CVE's and can't trust distro maintainers to do it" does in fact indicate that there is a deeper issue at play here. You might say "well, there's no implicit chain of trust here". You might be right, but is that really the most effective way of doing things? Of course Linux is Use it at your Own Risk, but is there not a concept of "we as a collective community should get together and try not to drop the ball on some serious shit?"
In terms of something actionable, and maybe someone more well versed in how the distros work can tell me why this is a bad idea, but shouldn't there be a documented process and channel for critical CVE's to be bubbled out to distro maintainers who then have some sort of SLA for patching them and sending them downstream to end users? Perhaps incentives are not aligned to produce this outcome.
To be more blunt: if you’re paying for a product, the vendor owes you whatever things they committed to. If you’re a Redhat customer and your agreed SLA with Redhat for this kind of security fix was passed by, go be mad at Redhat. (I don’t think Redhat is bad here, they’re just the vendor most known for a commercial offering from the lists here. I would say the same thing about Ubuntu Pro)
Otherwise, it’s on the end user. Distro volunteers don’t owe you anything. Kernel devs don’t owe you anything.
I don’t care about what would be the most effective way of doing things. I care about what folks involved actually owe to each other, and distro volunteers don’t owe users any kind of active chasing of remediation due to the user’s threat model.
The idea of making some kind of streamlined process that solves what you didn’t like about this vulnerability’s remediation is that it ignores basically all the complexity. Like “what about distros that don’t abide by embargoes” or “what distros count as ones that matter” or “what about all the vulns that aren’t in Linux, they’re in software that’s packaged across many operating systems”.
Right, you’re saying “system is working as designed”, and I’m agreeing, but I’m saying “the system as designed kind of sucks, how can we make it better”?
I disagree that it sucks. It leverages a ton of people putting in their time and resources, and relies on system operators being active participants.
This vulnerability is, for some threat models, a really big deal. A security group found the vulnerability. They disclosed it. It was patched.
Folks here have gotten all kinds of bent out of shape that the groups involved didnt do things in the way each internet commenter would have liked. But this is the system working.
> This vulnerability is, for some threat models, a really big deal.
This vulnerability is, for other threat models, a death sentence.
> A security group found the vulnerability. They disclosed it. It was patched.
It was patched only after some people who should have been notified well in advance happened to notice something was up. That is NOT HOW IT'S SUPPOSED TO WORK.
For as long as the unpatched window remains open, skids will mess around and break things. Organized crime teams will use it for some really nasty hacking/ransomware/exfil/extortion/whatever. I guarantee you, this vuln is powerful and widespread enough that intel orgs will use it to kill targets, if they haven't already been using it for years. And if they have, we can just bank on them pulling out all the stops to take advantage of the remaining time for wreaking havoc. Make a project out of it and see if you can guess some of the future headlines.
Certain folks might not care much because they are citizens of one or more of those orgs' nations, so those targets are welcome to die in their opinion. That's fine. You do you, I'll do me, we'll all just go on doing our thing. But it's all fun and games until the wrong target gets hit and now there's a pact between the Germans and the Austrians being invoked and a few dozen million Europeans die. Or a geopolitical hotspot flares up and overnight 20% of the global petroleum supply chain grinds to a halt. Use your imagination. This vuln is a digital magic wand that is trivially usable to cast Avada Kedavra and somebody neglected to tell 99.99% of the Good Guys about it.
How is this different from any other day? Because now we've got a world-changing vuln out in the wild with no distro mitigation on day 1, and who the hell knows how many unscrupulous actors poised to take advantage of it before the fun and games stops. There will be no adults in the room when the miscreants decide to deploy while they still can.
Is this vuln going to start the next world war? Probably not. I don't expect it to and I hope and pray it doesn't. But leaving a vuln like this undisclosed to the very people whose job it is to protect us all is playing with fire. Not matches; more like a 10-grams-less-than-critical mass of plutonium.
sam is right to be pissed and he's doing a very good job of hiding it, because he knows that his users are at the mercy of TPTB in the Linux kernel world. Somebody's head needs to roll for this, and I don't mean some dude the CIA wants to hax0r because he's next on the list.
> This vuln is a digital magic wand that is trivially usable to cast Avada Kedavra and somebody neglected to tell 99.99% of the Good Guys about it.
A Linux LPE is a nothingburger unless you’re relying on the Linux kernel to enforce internal security boundaries, which would simply be foolish.
Start a distro with your preferred upstream tracking policy.
Is that the only option here? It’s certainly being framed as such.
Fwiw, I'm completely with you on this. The folks you're communicating with seem utterly miserable, and don't seem to be communicating in good faith.
Not sure what the solution could/should be, but surely there could be a better, easier mechanism for kernel to advise all distro maintainers who care, and for those distro maintainers to subscribe in some way. Whether any distro maintainers do so (let alone do something about the vuln notifications) would be entirely up to them. There could also be some easier way for end users to see what the distros' policies on this are, such that they can take that into account when selecting a distro.
It seems odd to call me utterly miserable and then suggest I’m not communicating in good faith.
We don’t have to agree, but the site rules are pretty clear that swipes like that aren’t ok.
That kind of distro maintainers and kernel devs communication path already exists: the linux-distros@ mailing list. But since anybody can read it, posting “hey everybody, this is a security patch” has basically the same effect as the security researcher posting, in terms of disclosing the vuln to bad actors.
Given that anybody can make a Linux distro, and Linux distros aren’t generally either capable or interested in background checking their teams or policing their individual security practice, it doesn’t seem possible to have a communication channel that distros can sign up for that lacks this problem.
Just as a purely intellectual exercise, what changes about this if we leave aside ideas of "owe," "deserve ," and "earn?"
There's not really an enforcement mechanism in FOSS like there is in capitalism world, it just comes down to what we want our part of the world to look like. So I think we'd think more clearly if we leave aside the ideas like "who owes who what." I think it's fun to imagine what sort of motivations and incentives there are if we put away the money ones.
"leave aside ideas of "owe," "deserve ," and "earn?""
Nonsensical string of words with no meaning.
If you want something that someone else isn't giving you, you have the option to try to do it yourself, or try to compel someone else to give you what you want somehow. Feel free to idk pay someone to track the kernel list and 4000 others and send you heads-ups? Try to pass a law to make people do what you want since you don't care about words like "owe"?
> If you want something that someone else isn't giving you, you have the option to try to do it yourself, or try to compel someone else to give you what you want somehow.
Yes, exactly, the opposite of paying, since when you pay someone something they owe you whatever you paid for.
If we leave aside owe, deserve, and own, we can start discussing things like what we want our kernel ecosystem to look like, how we can make it safer, etc, without being burdened by these concepts.
It's a simple intellectual exercise, that's all. If you're having a strong reaction to it, imo that'd make it even more fun for you to participate.
The real advantage of Microsoft is that there is someone you can sue!
Linux like every open source project is just a bunch of people who are YOLOing it. Not something you use for your fortune 500 critical mission infrastructure.
https://github.com/microsoft/azurelinux
I thought this is why red has exists?
> Others backport what they feel are relevant.
But from what I understand they were not given enough information to know if it was relevant or not. The commit message just said it reverted a change from another commit because there was "no benefit". From the patch itself, it is not at all evident that this is a fix for a critical security bug.
> The commit message just said it reverted a change from another commit because there was "no benefit". From the patch itself, it is not at all evident that this is a fix for a critical security bug.
If the commit message says it fixes a security bug, then bad actors immediately know there's a possible exploit there. So maybe it's intentional? (not familiar with the policy for this)
Then we’re back to the initial problem. How can you fix and then communicate to downstream about security vulnerabilities without exposing those vulnerabilities in an open source project? If you want to reach all your possible users you have to disclose the vulnerability.
The accountability fundamentally lies with the distro maintainers. They're the ones shipping a "product". Either they need to get agreements in place for advance notice, or correctly set expectations with their users that they won't get advanced notice.
They dropped the ball when the shipped supposedly secure systems where their method for getting alerted to security updates was "hope people reporting to upstream will also notice a mailing list that will alert them".
(Caveat: Distro's like Ubuntu advertise security updates so this is on them. I'm not sure Gentoo does that, if they don't well then no one dropped the ball because no one represented that Gentoo got prompt security updates).
All it takes is to be part of the Kernel security team. I am surprised that many commercial strong distributors just not care enough to join the Kernel security team. Hopefully a valuable lesson was learned and fixes are applied.
The distros dropped the ball. imho. One of the (main) tasks of the distro is watching the changed of you upstream packages for important changes. This is slightly complicated by the fact that the linux kernel considers all bugfixes security fixes, so it's quite a lot to read it all. But that's life. The kernel developers are not wrong as it's nearly impossible to be sure a bug in the kernel is not (also) a security problem.
If they get enough time to build a website with a fancy logo instead, one might however question where their priorities are.
I'd imagine it's not that they lacked the time to email linux-distros, but that they were unaware they were supposed to do so.
Feels like the more sensible process would be for kernel maintainers to announce when a version contains a fix for a high-impact security vulnerability and for distro maintainers to pay attention to that. Could be done without revealing what the vulnerability actually is in most cases, trusting the kernel maintainer's judgement. There does seem to be a public linux-cve-announce mailing list.
Why is it the job of the kernel to notify the distros? Why isn't it the job of the distros to keep up on upstream security disclosures?
Expecting a FOSS project to go track down all of its (millions of?) users seems like a very unreasonable expectation, and is well outside of their scope of responsibility.
People have gotten so used to the Github flavour of free-labour, social-network-style FOSS that they've forgotten what all those LICENSE files actually say, which is to make it explicitly clear that the devs are not responsible to you for your issues, up to and including the software setting your house on fire. If you don't like it, you don't have to use it.
> Why isn't it the job of the distros to keep up on upstream security disclosures?
They can't, because (responsible) security disclosures are private, _not public_. That's the whole point of the system: notify the developers in private ahead of time (usually 30, 60 or 90 days) so they can write, test and roll-out the fixes before you release the info to the whole world. This is to minimize the time between when bad actors gain access to the exploits vs. when users install the patch. So "keeping up on security disclosures" cannot ever be a 'pull' process.
Usually the maintainers of the big distros are part of (private) security mailinglists and receive such info. Just not in this case it seems.
It would be best if distros kept tap on kernel changes and update as soon as possible when they see a security issue fixed.
Sending emails to some big distros would still result with e.g. Gentoo not getting that info because they are not a big distro.
The problem is that the kernel devs (correctly imo) consider all bugfixes security fixes. So the distros need to decide for themselves which ones are important enough to warrant an update. Apparently this one had a quite unclear commit message, so it importance was missed.
Not ideal, but also: shit happens? It's always a balancing act choosing the lesser of multiple evils and most of the time it seems to work ok-ish, which is probably the best we can hope for ;-P
The kernel maintainers don't flag "security fixes" as special, and they have a well-thought-out reason for that, see many other comments in this thread.
That, and they flag pretty much any random patch with a CVE these days, making it harder for distro maintainers to keep up.
For this specific "bug" they took care to not mention any security angle in the commit message, making it extremely hard for an outsider to even realize this was a critical patch. I assume this was because they wanted to push the fix without breaking embargo.
Where do you suggest they should have kept up on this disclosure?
> Expecting a FOSS project to go track down all of its (millions of?) users seems like a very unreasonable expectation, and is well outside of their scope of responsibility.
The post you are responding to says that it would be nice if they copied literally one mailing list.
> a notification should have gone out from the kernel team to a curated list of distro security folk
Who would curate that list though? You don't need permission from the kernel team to spin up a new distro. I can go and create fork of Debian or Arch or whatever today and the kernel team would never know (and neither should they).
This is completely in the responsibility of the distros. If you don't like this model, use something like FreeBSD.
Sounds like a job for the Linux Foundation maybe?
You don't need anyone's permission to make a distro, that's true, but if you notify Debian, Canonical, Fedora, Red Hat and Arch you're covering a very large fraction of users; way more than today's 0%. In cases like this, perfect is the enemy of the good.
A rogue actor may create a new distro, maybe for some niche use case such as accessibility or retro gaming. After acquiring enough false (and even some real) users that the Linux Foundation accepts them as a notifiable distro maintainer, this maintainer could then pwn machines before the exploit is made public.
I didn't say all distros should be notified, for that exact reason. I listed a handful of major fistros.
Who gets to decide who the lucky few are?
Sounds like a job for the Linux Foundation maybe?
Human beings
Qualified by what?
Rather than the current situation, where they can pwn machines after the exploit is made public?
Yes. After the exploit is made public, the window of opportunity closes quickly.
Uh, there is a list, named "linux-distros", which is for this purpose (and I think it's for more than just Linux, e.g. I believe it was used for the xz vuln).
Given this was announced when backports weren't ready (and given the POC was at least opaque if not obfuscated), I'm getting the vibe fixing the vuln wasn't as high as a priority as making a media splash.
From TFA:
> Note that for Linux kernel vulnerabilities, unless the reporter chooses > to bring it to the linux-distros ML, there is no heads-up to > distributions.
so, no, `linux-distros` list don't solve the problem.
The impacted user count of your debian fork with custom compiled kernel would probably not be more than 1 however.
> they are in a much better position to coordinate and communicate with the maintainers than random reporters are.
They openly refuse to do this and have been given authority by MITRE to work against any such process.
right, which is why it is confusing that the animosity is aimed at the reporters rather than the kernel security team.
I think both parties share some blame here.
Not really confusing. Linux is a sacred cow.
There would be a lot of people gloating if this happened to MS.
Microsoft has a long and sordid history of cheerfully doing anything they can to fuck everyone over just to make a few more percentage points of profit.
Linux is a free kernel that literally revolutionized the computing landscape.
Yes, this is the sacred cow status being referred to.
It might be a scared cow, but at least deservedly so. There is imho a difference between accidental incompetence (debatable, even) and active malice. Microsoft has done a lot of the latter so gets bashed more, nor surprise there.
What process? Wasn't the default state of things to just let any random person of the street spam vulnerability reports without validation or quality control?
Two things can be true simultaneously: the Linux kernel ecosystem should have done better at communicating this to their downstreams, and publicly sharing the exploit was irresponsible.
It is not the responsibility of the initial reporter to communicate to distributions, but the fact that those responsible failed to do that, doesn't give everybody else a free pass.
No, this was already timed disclosure. This is very common and widely accepted. 90+30 is what Google Project Zero uses, for example. The security researcher has met their ethical requirements already. This is entirely on the kernel's security team for failure to communicate downstream. That is their responsibility.
The thing is, malicous actors are already monitoring most major projects and doing either source analysis or binary analysis to figure out if changes were made to patch a vulnerability. So, as soon as you actually patch, you really need to disclose because all you're doing by not disclosing the vulnerability is handing the bad actors a free go. The black hats already know. You need to tell the white hats, too, so they can patch.
I'm not advocating for delaying the disclosure at all; my point is, if you see your initial disclosure to the kernel didn't go anywhere, to be responsible is to put in a little extra effort to ensure the fix is picked up before you disclose.
"Didn't go anywhere"? The kernel devs patched it! They patched it weeks ago! The kernel security team needs to communicate security problems in their own releases, because that is where the distros are already looking.
Requiring the security researcher to do it is insane. Should a security researcher that identifies a vulnerability in electron.js need to identify every possible project using electron.js to communicate with them the vulnerability exists? No. That's absurd.
The kernel devs patched it! They patched it weeks ago
FTFA:
> I see that on the 11th of April 6.19.12 & 6.18.22 were released with the fix backported.
> Longterm 6.12, 6.6, 6.1, 5.15, 5.10 have not received the fix and I don't see anything in the upstream stable queues yet as I write.
I wouldn't go so far as to call this "the kernel devs patched it". Virtually none of the kernels that distro's are actually using today have received a fix. This looks like an extremely lackluster response from the kernel security team.
Pretty much the only non-rolling distro's that are shipping a fixed kernel are Fedora 44 and Ubuntu 26.04, both released in the last few weeks. Their previous releases both shipped with Linux 6.17 which is still vulnerable today!
None of this impacts disclosure norms. One important reason the clock starts ticking faster once any patch lands is that for serious attackers, the patch discloses the vulnerability. That's quadruply so in 2026, when many orgs are automatically pumping Linux patches through LLM pipelines to qualify them for exploitability.
But it's been at least 15 years since "reversing means patches are effectively disclosures legible mostly to attackers" became a norm in software security. And that was for closed-source software (most notably Windows). The norms are even laxer for open source.
In the airless void of a message board thread, of course they should. What does it cost a commenter to demand that?
> Should a security researcher that identifies a vulnerability in electron.js need to identify _every_ possible project using electron.js to communicate with them the vulnerability exists? No. That's absurd.
But this is a false comparison, right? The scope of "Linux distributions" and "electron apps" are orders of magnitude different. If the reporter spot checked one or two of the most popular distributions to see if fixes had been adopted, that seems like an extra level of nice diligence before publicizing the details.
It doesn't seem "insane" as much as "not the most efficient path" as has already been well argued. But it also doesn't seem unreasonable to think in a project of the scope of the Linux kernel, with the potential impact of fairly effective(?) privilege escalation, some extra consideration is reasonable--certainly not "insane" at the very least?
They embargoed their vulnerability for 30 days after Linux landed a kernel patch. They did their part. You will always be able to come up with other things they could do for you, and they will always at first blush sound reasonable because of how big and important Linux is, but none of those things will be responsibilities of the vulnerability researcher. Their job is to bring information to light, not to manage downstreams.
About half the thread we're on reads as if the commenters believe Xint made this vulnerability. They did not: they alerted you to it. It was already there.
I realize you've been championing this idea in the thread, and I admire it because I also recognize the misdirected blame. Please understand I do not harbor "blame" for the researchers.
> Their job is to bring information to light, not to manage downstreams.
The researchers are also members of a community in which more harm than is necessary may be dealt by their actions. Nuance must exist in evaluating "reasonable" and "responsible" in the context of actions.
I strongly disagree. I want the information. I don't want to wait longer to find out about critical vulnerabilities so that researchers can fully genuflect to whatever Linux distribution norms people on message boards have. Their "actions" were to disclose a vulnerability that already existed and was putting people at risk. It's an absolute good.
If it helps you out any, even though my logic was absolutely the same and just as categorical in 2012 as it is today: there are now multiple automated projects that run every merged Linux commit through frontier models to scope them (the status quo ante of the patch) out for exploitability, and then add them to libraries of automatically-exploitable bugs.
People here are just mad that they heard about the bug. Serious attackers had this the moment it hit the kernel. This whole debate is kind of farcical. It's about a "real time" response this week to a disaster that struck a month ago.
I do get that, this era of automation is too responsive to not go public to provoke action. I think I might just be wistful of an era in which the alternate path might have made a difference. Sorry to pile on.
You're not piling on and I'm glad to have the opportunity to expand on my point.
>publicly sharing the exploit was irresponsible
they did it in the established industry standard way that probably every single security researcher you can think of follows (for good reason, i would add).
whoever did the marketing on "responsible disclosure" was a genius.
tptacek says it much better than me: ""Responsible disclosure" is an Orwellian term cooked up between @Stake and Microsoft and other large vendors to coerce researchers into synchronizing with vendor release schedules."
In my world, responsibility is not just checking a box of following industry practice. Responsibility, as Wikipedia puts it on their social responsibility page, is working together with others for the benefit of the community. And yes, sometimes that's a bit larger burden than would ideally be the case. It's an imperfect world, after all -- and let's not forget the disclosure as it happened also placed a larger burden than ideal on people scrambling to patch.
And it's not as if I'm asking for a lot of effort. One mail to the security team of a popular distro "hey, we have found this LPE that we'll release with exploit next week, it's patched upstream already in this commit, but you don't seem to have picked it up" would likely have been enough.
No.
The problem is that vendors and developers have repeatedly shown that if you give them an inch, they take a mile. Look at exactly what happened with BlueHammer this month. The security researcher went full disclosure because Microsoft didn't listen to their reports.
Disclosure is vital. It's essential. Because the truth is, if a security researcher has found it, it's extremely likely that it's already been found by either black hats or by state actors. Ignorance is not actually protection from exploitation.
The security researcher also has a responsibility to the general public that is still actively using vulnerable software in ignorance. They need to be protected from vendor and developer negligence as well as from exploits. And the only way to protect yourself from an exploit that hasn't yet been patched is to know that it is there.
The situation with e.g. BlueHammer is fundamentally different: there, the only party that could act on it (Microsoft) ignored them. In this case, the parties that could act on it weren't notified at all.
I'm also not proposing delaying the disclosure to the general public at all. They already waited 30 days with that, that's fine. Just look a bit further than your checklist of only contacting upstream, and send a mail to the distributions if they haven't picked it up a week or two before.
Downstream vulnerability disclosure is a negotiation between the downstreams and the upstreams. It is not the job of a vulnerability researcher to map this out perfectly (or at all).
Yes and that's why the current system where security researchers are expected to reach out to the distro mailing list is flawed and instead there should be a defined pipeline for the kernel security team to give a heads up.
> The problem is that vendors and developers have repeatedly shown that if you give them an inch, they take a mile.
[citation needed]
Is there any evidence that Linux distros (specifically) act in this way? Or a particular distro?
>[citation needed]
there is ~3 decades of citations you can look at, spread out over every security mailing list, security conference, etc. that you can think of.
one decent start is https://projectzero.google/vulnerability-disclosure-faq.html...
"Prior to Project Zero our researchers had tried a number of different disclosure policies, such as coordinated vulnerability disclosure. [...] "We used this model of disclosure for over a decade, and the results weren’t particularly compelling. Many fixes took over six months to be released, while some of our vulnerability reports went unfixed entirely! We were optimistic that vendors could do better, but we weren’t seeing the improvements to internal triage, patch development, testing, and release processes that we knew would provide the most benefit to users.
[...]
While every vulnerability disclosure policy has certain pros and cons, Project Zero has concluded that a 90-day disclosure deadline policy is currently the best option available for user security. Based on our experiences with using this policy for multiple years across thousands of vulnerability reports, we can say that we’re very satisfied with the results.
[...]
For example, we observed a 40% faster response time from one software vendor when comparing bugs reported against the same target over a 7-year period, while another software vendor doubled the regularity of their security updates in response to our policy."
>Linux distros (specifically) act in this way
carving out special exceptions based on nebulous criteria is a bad idea. 90+30 is what has been settled on, and mostly works.
Really?
Because I would call a situation where the development team fails to appreciate the severity of a security vulnerability and has an established procedure that requires the researcher and not the kernel team to communicate with downstream users is already a major failure of process. Security is not just patching the vulnerability, and it seems that the Linux kernel developers or the Linux kernel security team does not understand that.
This is the result of that failure.
If this were any other software, we'd be here with pitchforks and torches. The researcher gave the developers timed disclosure, and even waited until after the developers had patched the issue. And... it's still a problem.
so what? we should never disclose anything? this will only result in companies suppressing disclosure and leaving vulnerabilities unpatched.
If the maintainers were unresponsive, sure -- but it seems slightly hard to buy that a responsible reporter trying to make a big splash and a good impression wouldn't first check "did this make it out to the distros?" before making sysadmin's days real shitty, even if technically they could point fingers at other parties. At which point, if they're paying paying any attention at all to what they reported, they may have realized that a mistake was made.
its an industry standard disclosure process. 90 days after reporting, or 30 days after the patch lands, the vuln is disclosed.
the linux kernel team is in a 10000% better position to communicate to and coordinate their downstreams. it seems completely backwards to me to suggest that the reporter should be responsible for figuring out every possible downstream and opening up separate reports to each of them.
the kernel team should have a process/channel to say "this is important! disclosure is in 30 days" that is received by distro security teams. because this is not the first or last time the kernel will have a local privilege escalation. hoping that every reporter, forever in the future, will take the onus on themselves is a recipe for disapointment.
The problem is that if you make too big of a deal about a particular patch, then someone just reverse engineers the vuln from the fix and your responsible disclosure period doesn't exist anymore.
Gentoo has to take some blame too for not keeping all the kernels they maintain patched in a timely way.
> Gentoo has to take some blame too for not keeping all the kernels they maintain patched in a timely way.
How do you figure that? From what I could tell from the earlier post, the fix has only been backported to 6.18 and later, and as TFA indicates the distro's were not informed of the security implications of this fix. All distro's shipping a major kernel version from more than a year ago -- and that includes all LTS kernels -- are vulnerable, regardless of how "timely" their patch schedules follow upstream.
you minimize this with the curated contact list.
the baddies are looking at every patch anyways.
Yes, it's just incompetence from everyone involved, not malice. The company making the disclosure doesn't actually care, and the kernel processes are ineffective.
No, it's incompetence from everyone involved except the company making the disclosure, which, despite the fact that the existing norms are not in fact binding (like people downthread seem to believe), they followed.
Really? It seems very odd to not check in on the status of the fixes, even if it's technically possible to pass the blame to other people.
Even if the only purpose of looking at the status to make yourself look good in marketing materials, it's surprising that it didn't happen.
`it's technically possible to pass the blame to other people` presupposes that the blame belongs to the reporter unless effort is taken to "shift" it. This is just an inaccurate worldview as many people have pointed out clearly in this discussion. If there's a vulnerability in software the blame lies with people who wrote and maintain the software, not someone who finds and discloses a vulnerability. The person who should `check in on the status of the fixes` is the person who owns the thing being fixed, which is very much the kernel and distro maintainers and not the security researcher. It is you who are willfully shifting blame to an innocent party
One of the reasons this unavoidable deadline was invented, is that the alternative is that one company (or all of them) can simply decide to ignore the vuln report, and then the vulnerability will stay forever undisclosed and forever out there in the wild. And prisoner's dilemma suggests that most companies would chose "do nothing" in this scenario: they don't have to do anything, and if the vuln stays undisclosed, it probably won't be exploited anyhow. Win-win!
I'm confused. Can you explain how this applies to the current situation, where no vuln reports were submitted to the groups responsible for distributing patches?
>where no vuln reports were submitted to the groups responsible for distributing patches?
the vulnerability report was submitted to the kernel security team and appropriate kernel maintainers. those are the people responsible for patching the kernel, which they did 30 days ago.
> those are the people responsible for patching the kernel, which they did 30 days ago.
They patched 2 of 7 supported kernels.
Guess the other supported kernels aren't supported enough
I see, may the people who are responsible for the infrastructure you depend on be less concerned about shifting blame than you are.
imagine you use a dependency in your code. like left-pad. and some vulnerability is found in left-pad.
is the reporter of that vulnerability responsible for finding and submitting a vulnerability report to every single piece of software that uses left-pad? all ~millions of them?
or do they submit the report to left-pad, get them to fix it at the source, and trust that the people relying on left-pad will update their software like they should when they see a security-relevant update is available?
> the groups responsible for distributing patches?
Those groups don't exist, to my knowledge. And probably can't, realistically speaking.
The disclosure was more about marketing than security. From the disclosure page:
> Is your software AI-era safe?
> Copy Fail was surfaced by Xint Code about an hour of scan time against the Linux crypto/ subsystem. [...]
> [Try Xint Code]
More chaos makes their product seem even more attractive.
I worked at the industry's first commercial vulnerability lab (Secure Networks) in the mid-90s, and many of my friends at the time founded X-Force. Commercial vulnerability research has always been about marketing: marketing pays for the vulnerability research. That doesn't make it any less prosocial.
I created an account for xint code, wtf is this UX?
I get put into a read-only dashboard with ZERO info. is this live? is this static? how do I use it? the API button just leads me to a swagger doc.
Your advertising for them on HN would help them too, I bet.
Does it? Now that I see their name again in this context they're blacklisted for life.
hope you are also blacklisting google's project zero, and practically every other major player in the vulnerability reporting space, as all use roughly the same bog standard 90+30 policy.
this was a failure of the kernel security team, and their stance on communicating security issues with their downstreams.
What are they blacklisted from exactly? The benefit you get from them forcing vendors to make their software more secure?
Same. They do become famous, but not in a wholly positive way.
I used to think the context of the fame mattered. At least in the US, it does not.
Hell, Crowdstrike is still purchased.
Researchers are under no obligation to engage in coordinated disclosure and are free to sell 0day for profit. Just fyi. Be glad it was disclosed at all. Be glad a patch was available prior to release.
If they want to be seen as responsible rather than opportunistic, then yeah, they should do a proper coordinated disclosure.
Sure, they have no legal obligation to disclose, but we all also have no legal obligation to buy their services. Blacklisting bad actors like this is the right move to discourage this kind of behavior.
>they should do a proper coordinated disclosure.
they did a proper coordinated disclosure, following the industry standard 90+30 process. that is why the exploit dropped 30 days after the patch landed.
the kernel team should have communicated with their downstream about the importance of the patch. that is the kernel security team's responsibility -- and they are much better positioned to do that than crossing your fingers and hoping every reporter will contact every distro every single time there is a vulnerability.
there are very good reasons disclosure works this way, backed by a couple of decades of debate about it.
how many times it has to be said that it is impossible for linux kernel to communicate with anything but a minuscule portion of its downstream and _that_ has been done?
Who cares about how you are seen when you are selling 0day for big bucks? The bad actor makes more money than the 'legitimate' one without breaking any law. Punishing someone who didn't alert distros despite a patch being available encourages the company to simply find flaws and sell them for profit - it pays more to begin with.
If they want to take advantage of disclosure for marketing, they're either going to need to accept the norms around responsible disclosure, or they're going to need to accept how shirking those norms will come off. That's life in society. Sometimes it's annoying and sometimes it doesn't feel rational, but these norms have been negotiated throughout the history of our industry and are the way they are for reasons good and bad.
I just don't see the point in complaining about how shirking the norms of your industry will make you look irresponsible. I don't really care that they could have decided to sell the vulnerability instead. It isn't material.
It is absolutely not true that viable commercial vulnerability labs need to "accept the norms around responsible disclosure". There are no such norms. "Responsible disclosure" is an Orwellian term cooked up between @Stake and Microsoft and other large vendors to coerce researchers into synchronizing with vendor release schedules. It was fantastically successful at that, and it's worth pushing back on at every opportunity.
Tavis Ormandy dropped Zenbleed right onto Twitter. He's doing fine. You can blacklist him if you want; I imagine he's not going to notice.
Microsoft's policy is: "if you contact us with a vulnerability, you automatically agree to the terms of our responsible disclosure policy", which includes waiting 30 days after patch was created, and says nothing about how long that process takes.
There is actually no way to give them a friendly heads up, and then do your own thing. The only way not to be bound is by not sending them any notification at all...
> terms of our responsible disclosure policy
I couldn't find a public copy of that.
The best starting point I found for reporting vulnerabilities was: https://github.com/microsoft/MSRC-Security-Research/security...
You can email without agreeing to anything. But for a serious issue Microsoft would obviously try and track down who you are and what jurisdiction you are in.
https://www.microsoft.com/en-us/msrc/bounty-guidelines
> MICROSOFT BOUNTY TERMS & CONDITIONS
> Last updated: July 23, 2025
> The Microsoft Bug Bounty Programs Terms and Conditions ("Terms") cover your participation in the Microsoft Bug Bounty Program (the "Program"). These Terms are between you and Microsoft Corporation ("Microsoft," "us" or "we"). By submitting any vulnerabilities to Microsoft or otherwise participating in the Program in any manner, you accept these Terms.
Who knows if its enforceable.
This seems to be sloppy wording, with the intent of "we only offer the bounty under these terms". Maybe my interpretation is too charitable.
I wonder if "if you contact us... you automatically agree" stands in court. That's just ridiculous.
Reader, it does not.
Since no contract is signed, this is just pure fantasy from your part.
You're right, they don't need to. They have an alternative, to accept what people say or think about them in response. That's what I said.
So how do we feel about Linux distributors who have their heads up their asses and sat on their hands for 30 days?
Those norms do not exist. Those are people asking companies to do stuff to benefit the person complaining for free, and many companies will not do that.
It seems to me you're unaware of them, but there are strong norms around disclosure. They've been discussed for decades. It is the expectation that vendors would be notified in a scenario like this.
No, there are users who want those to be norms. Qualified researchers happily sell substantive vulns to people who pay (Governments/Cellebrite and companies like that) enough to quell any complaint.
Which is again, irrelevant to the question of how disclosure works and what expectations there are around it because that is not disclosure and is not what was being discussed.
it’s called building and preserving a high trust society, you wouldn’t understand
How does someone being incentivized to sell a vulnerability to a private organization over disclosing it publicly preserve a "high trust society"? Do you mean in the context of a "deceptively high-trust society"?
Those private actors aren't planning to sit around and hold onto these exploits they've horded forevermore, they're obviously paying for them so they can one day use them.
Unfortunately this is correct. As a security researcher I set millions in profit on fire for reporting vulns to projects that offer no bounties vs selling to highest bidder. I keep doing it because it is the right thing to do, but I would not blame someone that needs to feed their family making a different choice.
We must get public funds to reward ethical disclosure of big impact vulns like this.
Harder and harder to get good policy like what you describe when tech-adjacent people loudly argue for criminal penalties for anything other than coordinated disclosure :(
> criminal penalties
Mostly cover citizens within a very limited set of jurisdictions.
Otherwise there's a chance at extradition.
> are free to sell 0day for profit.
This is not true in many jurisdictions.
Anyone can sell a vuln in any jurisdiction and never be caught. Lets not pretend the law is actually worth a damn here.
We need an anonymous bounty system.
Are you claiming that if I sell 0day through a broker to the national Government of a given jurisdictions that the national Government of that jurisdiction is going to criminally penalize me?
If so, that's a bit naive. In the actual world, that buyer wants to buy more stuff from me, not penalize me.
I'm pretty sure they have a legal obligation in most jurisdictions not to sell 0days for profit.
And they absolutely have a moral obligation to do things in a way to minimize damage and impact to other people's systems. (I'm not saying "responsible disclosure" is the correct way to do that, but hoarding vulnerabilities and exploits and selling them to the highest bidder certainly isn't.)
This is how society needs to work.
It is categorically false that there's a legal obligation not to sell vulnerabilities. There's an obligation not to knowingly sell them directly to ongoing criminal enterprises. That's it. Plenty of people make fuckloads of money selling vulnerabilities for exploitation rather than repair.
Let me make you aware of zerodium. A broker anyone can sell vulns to, that sells to unspecified buyers you do not need to know about.
FWIW, zerodium shut down in 2025.
Or at least went dark ..
(The buyers are the NSA, the IDF, Cellebrite, NSO and its successor corporation and that kind of thing. Depends on what you are offering)
You'll learn who the buyers are if you routinely have the really good stuff to sell! If you are offering iOS zero click on a semi-regular basis, the buyer is going to want to try to deal with you directly and preferably offer you a more regular form of employment, if you are interested. Some national governments may offer certain benefits to you, depending on your situation.
All depends on what you have to offer. If you were able to offer this https://arstechnica.com/security/2025/09/microsofts-entra-id... or something of that magnitude, a lot of problems in your life would just go away. The buyers would all be Five Eyes and the intelligence gain of having that kind of access even briefly is priceless.
In a more Western-centric context, imagine if you had a flaw like that, same 'no logs are generated' and 'every single customer account is accessible' but the impacted vendor was Alibaba Cloud. The researcher would get to name their price. That's the real world, that's the world we share. We shouldn't be blind to that.
> I'm pretty sure they have a legal obligation in most jurisdictions not to sell 0days for profit.
it wasn't sold for profit, it was openly disclosed.
> And they absolutely have a moral obligation to do things in a way to minimize damage and impact to other people's systems.
All that "responsible disclosure" does is keep people from demanding better.
mmmmmm, no it would seem like they are absolutely under a social obligation to not do that.
> Researchers are under no obligation to engage in coordinated disclosure and are free to sell 0day for profit.
Uh... no? If you mean legally, some people might, depending on jurisdiction. But also, ethically? yes, researchers are ethically obligated to disclose responsibly.
> Just fyi.
...
> Be glad it was disclosed at all. Be glad a patch was available prior to release.
I am glad that a patch was available. Equally I can be glad that the linux community is strong enough to respond quickly, while also being angry that this person behaves unethically.
Likewise, when people in my industry behave poorly, or unethically; I'm now the person ethically obligated to both point it out, and condemn it. Not to become an apologist demanding I should be happy watching bad things happen, when much of the fallout could have been prevented with a bit less incompetence and ignorance.
> Researchers are under no obligation to engage in coordinated disclosure and are free to sell 0day for profit. Just fyi. Be glad it was disclosed at all.
I'm so glad these so called "researchers" aren't totally evil, I'm so grateful they're only half evil, give them a lollipop.
Whatever, the way they disclosed it isn't much different from no disclosure at all - the exploit would have been identified in the wild and fixed soon thereafter.
"Researchers"...
the way the disclosed it is the industry standard. think of the biggest security research teams you know (e.g. google), and they follow the same process.
non-security people always seem to get up in arms about it, but there is very good reasons why the industry has landed on the process it has, which has been hashed out over a few decades.
There are two options:
1. Status quo. Researchers are free to disclose to a vendor, free to sell vulns to legitimate companies, free to do full disclosure if they want. This situation benefits security. Researchers are able to pay their bills while also doing meaningful research into OSS projects that are unable to fund the kind of security audit they need. Harm reduction, of sorts.
2. Everyone is a bad actor. No one is going to do this work for free/for a bounty. Horrible flaws will be found and shared with ransomware gangs and the like. 0day will sell for a percentage of the ransom winnings. Researchers will live like kings, everyone else will suffer.
Which do you prefer?
They should have a legal obligation to engage in coordinated/responsible disclosure, and it should be a crime to sell or disclose a 0day to anyone other than a state-designated security organization or the vendor/provider.
If it won’t be handled through criminal law then it’ll be handled through civil litigation: Anyone who was exploited as a result of this disclosure should sue the discloser for contributing to the damage they’ve suffered.
Yes, exactly. Name and shame.
Same. I did not know who they were, but now they have been named and shamed. Not every publicity is good.
It is the opposite for me. I did not know who they are and now I have a positive opinion of them.
To be clear, the vulnerability existed in Linux, not in Xint Code. It existed whether this group disclosed it or not. Knowledge of it and exploits may have already been bought and sold among various groups with various motives including crime, terrorism, or cyberwarfare who likely made good money off it if this happened.
In that world, the vulnerability has more value to those who seek to exploit it for their own motives, regardless of the consequences. They hope that no one else stumbles on it and fixes it, preventing them from continuing to use it to do bad things.
In the world where it is disclosed, there is more value in fixing the vulnerability as the maintainer’s reputation is at risk (and potentially monetary loss or legal liability if they are shown to be negligent).
Yes, and that's why we have the responsible disclosure protocol. It wasn't correctly followed here.
There is no such thing as "the responsible disclosure protocol". There's really no such thing as "responsible disclosure" at all, but "the responsible disclosure protocol" is a term I have literally never heard before. (I've been a vulnerability researcher since the mid-1990s, for what it's worth.)
https://en.wikipedia.org/wiki/Coordinated_vulnerability_disc...
> In computer security, coordinated vulnerability disclosure (CVD, sometimes known as responsible disclosure)
I guess you can learn something new after 36 years.
If you are referring to what you quoted, your pedantry and sharpshooting would result in an incomplete English sentence: "that's why we have the responsible disclosure" is missing a noun. Now that we are firmly in worthless pedantry:
Protocol (n):
1.a. a system of rules that explain the correct conduct and procedures to be followed in formal situations
1.b. a set of conventions governing the treatment and especially the formatting of data in an electronic communications system
If you don't like what I said or disagree, poke holes in factual inaccuracies. However, in the reality that I am pretty sure we all share, responsible disclosure is a well established protocol that is followed by many security researchers, and was imperfectly followed here.
Which part was not correctly followed?
> It was extremely irresponsible
As a user and admin I disagree. Makes one appreciate what a masterful bit of lexical-engineering “Responsible” Disclosure is, kinda like “Secure” (from me, not forme) Boot — “Responsible” Disclosure is 100% about reputation-management for the various corporation/foundation middleman entities sitting between me and my computer.
Those groups don't care that my individual computer is vulnerable but about nobody being able to say “RHEL is vulnerable” or “Ubuntu is vulnerable”. The vulnerability exists for me either way, and I'd rather have the chance to know about it and minimize risk than to be surprised by the fix and hope nothing bad happened in that meantime.
Immediate public disclosure is the only choice that isn't irresponsible as far as I'm concerned.
So if I found a vulnerability that lets hackers withdraw withdraw all the money in your account without a trail on where the money went, you'd be fine with them disclosing it to the public at the same time as the bank learns about it?
Even when there is no known use case of the attack (other than the security researcher's)?
> The vulnerability exists for me either way, and I'd rather have the chance to know about it and minimize risk
By the time you hear about it, the money could be gone because 1000 hackers heard about it from the researcher before you did.
> than to be surprised by the fix and hope nothing bad happened in that meantime.
Hope is not a good strategy here.
Yep, I'd be fine with that. My bank has insurance, and my money would be returned.
Seeing your other (rightfully flagged) reply I want to tell you as a neutral party that yes this is missing the point of the analogy. You're basically saying "I would simply hit the brakes on the trolley". It's not that they're so hubristic they think it's impossible to legitimately disagree with their argument, it's that mentioning insurance is sidestepping their argument entirely. You're not addressing the general idea of getting hacked and suffering the consequences of the hack.
Just socialize losses and all is well.
What could possibly go wrong?
that is basically how all large companies behave anyway. socialize the losses (bailouts, layoffs, negative economic impacts in the communities they reside, etc.) and privatize the gains.
> that is basically how all large companies behave anyway
And do you agree with that behaviour?
nope
The banks cost of insurance goes up, cost of running an account goes up, how do we correct for this? offer worse accounts to customers...
Why do you assume banks would keep on doing the same old thing but paying more because of it? The cost would make them learn not to design systems where something like this hypothetical scenario was possible.
You're missing the point (not sure if you're just being dense on purpose...). If you're bank would just return the money then its not a good analogy. If someone gains root access to your machine, presumably they can do damage that can't be undone. In other words, to continue the bank analogy, they would take all your money and you would have no way of getting it back. Presumably, you would not be ok with this. And even if, for some weird reason, you were ok with that, 99.9% of all other people would not be ok with it.
Respectfully, I don't think they're missing the point. Banking, as an institution, has its flaws, but deposit insurance isn't one of them. These vulnerabilities exist whether or not they follow specific disclosure rituals, and systems should be deployed with defense-in-depth so that one privilege-escalation flaw is a recoverable event. Inventing tortured counterfactual analogies doesn't change the basic thrust of the poster's point: the account is insured, so getting drained by an attacker is not a fatal problem. Of course people should still take steps to prevent that from happening, but that doesn't mean prevention is (or should be) the only cure.
My point specifically is that some damage isn't recoverable if there's a vulnerability that gives someone root access. This makes the bank analogy inadequate in the first place. Im not trying to argue about whether deposit insurance is good or bad. Saying they would get the money back assumes the damage done to ones machine would be recoverable, which may not be the case.
My understanding is that FDIC deposit insurance only protects against bank failure, not fraudulent activity. Getting your account drained by an attacker may or may not be covered by a patchwork of other laws at various levels, and you could very well end up shit out of luck.
And what is the insurance in the Linux case, for which the analogy was being made?
Linux was informed properly, and the vuln was not disclosed until 30 days after the kernel was patched.
The real debate here is what went wrong with getting that info downstream, and whose responsibility was that?
"I, personally am not affected, and I don't care about anyone else so therefore there are no consequences"
> Immediate public disclosure is the only choice that isn't irresponsible as far as I'm concerned.
No, it's really not.
High severity vulnerabilities are responsibly handled by quietly neutralising them with subtle patches that do not reveal the vulnerability, waiting for those patches to distribute. Then patching or removing the root cause of the vulnerability (at which point opportunists will start to notice), and finally publicly disclosing it when there are already good mitigations in place.
Example: spectre/meltdowm mitigations.
I've been asked to use this approach myself when reaching out to maintainers. Sometimes it's possible to directly fix the vulnerability as a "side effect" by making a legitimate adjacent change.
With immediate disclosure the provider can decide to shut down while it is fixed. Or to notify users and make it their decision. Or to be prepared with a diversified infra and switch over to a non-vulnerable path. e.g, BSDs are not affected by CopyFail
“The choice that maximizes potential damage isn’t irresponsible, because it means I can mitigate my own systems immediately.”
That’s what you’re saying here.
They're literally just restating the argument for full disclosure security. This is one of the oldest debates in information security.
The disclosure doesn't appear very "full". Looks like this was slipped into mainline linux among dozens of other mostly-irrelevant "CVEs" with nobody highlighting the fact that it is in fact dirty-cow-on-steroids.
https://x.com/spendergrsec/status/2049566830771970483
https://lore.kernel.org/linux-cve-announce/2026042214-CVE-20...
Or is everyone expected to upgrade and reboot every 48 hours for all eternity and just deal with potential regressions all the time?
I think this reflects poorly on the original reporters. If you have a weaponized 700-byte universal local root exploit script ready to go, perhaps you should coordinate with major distros for patches to be available before unleashing it on the world. No matter how "veteran" you are.
Um, yes, everyone is expected to upgrade and reboot on a moment's notice. No policy or norm you come up with will change that.
(This bug does not technically require a reboot to mitigate).
I think I must misunderstand. Are you saying that you upgrade and reboot every production system that you administer to apply each commit to the kernel (branch it's using) essentially immediately? That doesn't make sense to me for a few reasons, but I struggle to find a different reading that applies "upgrade and reboot on a moment's notice" to the "slipped into mainline linux" scenario. Kindly help me to do so.
No: your posture with respect to having to cycle servers is a super complicated subject and you address it both with process and with architecture (for instance: you can be blasé about things like CopyFail if you don't allow multitenant shared-kernel in your design in the first place). But no matter what process and design you have, if you're hosting sensitive workloads, you always have to be in a position where you can metabolize having to cycle your servers.
It's a category error to talk about a disclosure event like this as something that would destabilize someone's fleet operations. The Linux kernel is fallible. So is the x64 architecture. You already have to be ready to lock things down and reboot (or mitigate) at a moment's notice.
Remember: whatever else grumpy sysadmins have to say about this, Xint are the good guys. Contrast them with the bad guys, who have vulnerabilities just as bad as CopyFail, but aren't disclosing them at all --- you only find out about them when it's discovered they're actively be exploited. There's no patch at all. There isn't even a characterization of how they work, so that you could quickly see what to seccomp. That's the actual threat environment serious Linux shops operate in.
LPEs are not rare.
Oh, I thought you meant "everyone" in a sense including actual human persons and the devices on their home network.
I find it curious to call someone dropping a weaponized root exploit before major distros or even LTS kernel git branches have patches ready "good guys". This could have been handled with much more grace.
To be fair, once Xint gave the heads up and the kernel team committed a patch, what was Xint supposed to do? Keep asking the kernel security team to backport patches for the LTS kernels?
As soon as a patch is committed, the clock starts ticking, the exploit will be discovered by reverse engineering recent commits. The commit was made on April 1st, Xint disclosed it on the 29th. If the Kernel Security team had wanted to, they had 28 days to backport patches in the LTS branches...
So, I wouldn't put any blame on Xint there.
Again: I made the actual distinction between bad guys and good guys clear. Good guys don't become bad guys simply because kernel security is an inconvenience to you.
There are more than just good guys and bad guys; in particular, there are also opportunists.
Opportunists are the ones who will sell a 0day to bad guys. Or who will drop a 0day publicly to promote their services. And they’ll fight tooth and nail against any actual legal obligation to engage in responsible and coordinated disclosure, because they make more money without that.
What the heck is up with people today.
Using quotes around something where you’re actually doing a strawman paraphrase of another commenter you disagree with is bad form.
It was clear that the original comment didn't say that, since we can see it right above. It was clear to me that the GP was using quotes as a way to use direct speech, not to imply that the GP literally said those words.
Those groups care about whether millions of computers are vulnerable, likely including your computer. If "immediate public disclosure" was done in all cases every vuln would be exploited and patches would be much lower quality. Shortening the disclosure timeline might be a good idea, 90 days is starting to feel long.
Millions of computers are still vulnerable. Not-knowing about it doesn't mean the vuln isn't there :p
Being vulnerable is not the important part. They have been vulnerable for years. The problem is the probability of being exploited. If everyone knows about the exploit details before a proper patch is available the number of exploited systems will skyrocket
But now millions more people know about how to exploit it who didn't before. I don't see why you're struggling with this.
You can't bully me into agreeing with you. Why are you struggling with that?
The Venn diagram of mainstream distros and individual Linux users is virtually a circle.
Ubuntu/RHEL is vulnerable and so are most Linux users by extension.
Without taking a position on the disclosure mechanics: any hosting provider hacked with this was already playing to lose. It is not OK to run competing untrusted tenant workloads under a single shared kernel. Kernel LPEs are not rare. This was a particularly simple and portable one, but the underlying raw capability is a CNE commodity.
> Kernel LPEs are not rare. This was a particularly simple and portable one, but the underlying raw capability is a CNE commodity.
I absolutely 100% agree with this and I'm glad to see somebody saying it. Any system that is one LPE away from being compromised is already insecure.
The Linux kernel is not usable as a security boundary, so anyone who wants to do "shared hosting" and not be hacked needs to use something else, like gVisor or firecracker VMs
The only important system that uses it as a security boundary is Android and there is mitigated by the fact that APKs need user approval, plus strict SELinux and seccomp policy plus the GrapheneOS hardening, and in this case the mitigations succeeded (https://discuss.grapheneos.org/d/35110-grapheneos-is-protect...)
A LOT of websites are tenants on WHM/CPanel hosts. Not to mention how many agencies use it for their clients Wordpress sites.
They built it wrong.
I thought that was the entire design goal of the Unix model, didn't it originate in the times when hundreds of users logged on to a shared mainframe? There are still public Unix servers like SDF out there. SELinux is just an extra layer so that if someone gets root (ex. due to an exploit in your setuid code or cron jobs etc) it's not game over.
I'm quite sure there are many application hosting providers which rely on container runtime such as runC (default runtime of containerd/Docker), and a shared kernel between users.
In a just world, those companies would be held legally accountable for negligent practices. The Linux kernel upstream has made it clear for decades that security is a dirty word.
LPEs on Linux are obscenely commonplace.
Expecting people to do the right thing is a fundamental issue here. Why would you ever expect for all of vulnerabilities to be disclosed privately? There's very little actual incentive to do this.
I'm honestly unaware of what systems could be put in place to prevent this but expecting people to always do the right thing is fantasy level thinking. I mean I bet the disclosers thought they were doing the right thing, hence why it's a bad thing to rely on.
edit: spelling/grammer.
When the exploit is an advertisement for an exploit detection company, not doing the right thing is a bad look
The worst thing would be to exploit or sell it for profit. Instead of that, publicizing the exploit is closer to neutral–good in my books, that did trigger a really quick reaction from the different actors to patch their kernels and systems
Imagine how much quicker the distros would have reacted if they were given a heads up a month ago. But, sure, I guess kudos to this company for not being actively criminal, and merely bumblingly incompetent and overly eager to get their marketing pitch out the door.
to which distros? how do you ensure fairness? Do you report this to the maintainer of Red Star OS (north korea)?
The kernel security team was given the heads up a month ago. At that point it is their decision.
There are channels like the distro security mailing list https://oss-security.openwall.org/wiki/mailing-lists/distros for this purpose.
Why don't all these distro maintainers add their own back doors, and mine crypto off our machines without our knowledge? Surely, there is some legal fine print they can add that would let them do that. There is very little incentive for them to maintain these systems, given how thankless and underpaid the work is.
Most distros are maintained by commercial companies.
Why wouldn't the linux security team notify the main linux distributions?
Greg and Linus do not believe in the entire concept of "vulnerabilities" in the Linux kernel and do not believe in the methods that distros use like cherry picking, therefor they typically are against issuing CVEs, scoring CVEs, describing vulnerabilities at all (if you use the word "vulnerability", your patch will be rejected), etc.
It's fundamentally their position to not work the way that you describe.
I would like to read more about this. Do you have a source?
http://www.kroah.com/log/blog/2026/02/16/linux-cve-assignmen...
I'd start with Greg's on words. You can probably find more on it from Spender/grsecurity's blog.
That doesn't really seem to map onto the situation since Greg himself released a 6.12 with the patch earlier today.
I don't know what you mean at all. I'm just repeating known kernel policy here. What does 6.12 have to do with anything?
What is your interpretation of why Greg KH released a version of 6.12 with this fix in it today, other than to help distributions avoid this vulnerability?
Why would he ever... not release a new version???? The commit for a fix was in early April, you know.
Partly they already have enough on their plate. It's up to the reporter to pick how to handle the disclosure, and unless a specific maintainer chooses to handle it, the Linux security team clearly says they won't.
Partly they have a strong belief that all kernel bugs are vulnerabilities and all vulnerabilities are just bugs; sometimes taken to the extreme in both ways (on one hand this case where the vulnerability is almost ignored; on the other hand, I saw cases where a VM panic that could be triggered only by a misbehaving host—which could just choose to stop executing the VM—was given a CVE).
This couldn't be more backwards. This has literally nothing to do with bandwidth. The kernel is a CNA, they are explicitly the ones to do this.
The reason they don't is because Linus and Greg have repeatedly, publicly stated that they don't want to because they don't believe that vulnerabilities conceptually make sense for the linux kernel and they refuse to engage in the process.
> they don't believe that vulnerabilities conceptually make sense
That's exactly what I wrote: "they have a strong belief that all kernel bugs are vulnerabilities and all vulnerabilities are just bugs; sometimes taken to the extreme in both ways".
But there is also a question of bandwidth. If a maintainer asks to bring a specific vulnerability to distros-list, the kernel security people will be reasonable. I did it last March.
Seems a little crazy. Somebody should evaluate blast radius and do appropriate distro notifications in a case like this (I presume the impact was part of the disclosure, so not much extra work).
You know the linux kernel is a free software project right? If you think “somebody should” do a thing but you aren’t prepared to do it yourself then you should maybe ask for a full refund.
Thank you very much, seanhunter. You hit the nail on the head there.
Not really, because they made Linux a CNA specifically to own the process and distort it the way they want it to be.
Well, how do you define main Linux distros? Isn’t the next smaller one not receiving the info always complaining?
> Well, how do you define main Linux distros? Isn’t the next smaller one not receiving the info always complaining?
For a first approximation: Ubuntu, Debian, RHEL(-derived) to begin with, and SuSE which is in EU/server space (AIUI):
* https://commandlinux.com/statistics/most-popular-linux-distr...
* https://commandlinux.com/statistics/linux-server-market-shar...
Seems like Gentoo, Arch, Mint, and Slackware could also be as well:
* https://distrowatch.com/dwres.php?resource=major
U/Deb/RHEL are 'upstream' of a lot of other projects, and fixes would trickle down to Rocky, Alma, etc. Perhaps VM OS in cloud (AWS, Azure) could be a usage gauge as well.
Isn't there already a distro security list for this purpose?
Yes.
Because one of them might have an incentive to not do so. In this case it's because they want to advertise their own company.
I can accept (and welcome) disclosure before there are patches.
But publishing a working exploit together with the disclosure before patches are available is really really irresponsible, maybe even criminal.
And no, the proposed mitigations don't help with half of the distributions out there...
The patch was available. Upstream just doesn't communicate vulnerabilities because they have a personal dispute with distros about how to handle patching.
> maybe even criminal
What’s your theory here? What crime?
Exploits are sold and used as weapons, sometimes even weapons of war. Which in many places is criminal, except under very restrictive circumstances.
Also, all kinds of aiding and abetting.
What does that have to do with this comment thread?
Copying from the comment I was replying to:
> But publishing a working exploit together with the disclosure before patches are available is really really irresponsible, maybe even criminal
If it's not a crime I see no reason not to work with partner nations to build responsible disclosure into a legal framework everywhere because it pretty obviously should be.
If you wanted to somehow make coordinated disclosure into a legal framework, that would be an interesting and complex project.
But it’s not the law anywhere I’m aware of today, and I’d not support it becoming a law.
This is kind of a thing already in the EU. Under NIS 2, vulnerabilities should be notified to a CSIRT as well as upstream, and the CSIRT shall identify downstream vendors and negotiate a disclosure timeline. I don't know whether they're any good at it or not, though.
You know companies are allowed to pay people to find vulns, and pay people bug bounties?
Instead of that, you’d rather make the law compel free individuals to limit their speech, or to hand over their work to big companies privately, so big companies can save money?
That doesn’t sound like a nice future, if it’s even enforceable at all.
AIUI the exploit was fairly low-effort once you knew the vulnerability. So publishing one probably didn't change the landscape much.
There is an alternative mitigation you can use which blacklists the function calls when the affected code is not built as a kernel module.
> alternative mitigation you can use
That's besides the point. If people use the official mitigation on https://copy.fail/#mitigation they will not sufficiently protect themselves on mainstream distros like Ubuntu and Debian.
The page also states
> Most major distributions are shipping the fix now.
This text was probably prepared in advance, but this was simply not true at the time of publication.
Patches were available for nearly a month.
Basic care would involve making sure the patches had made it into the wild before ending the embargo, and nagging the relevant parties if not.
Edit: As of this writing, most distros including Redhat, Fedora, Debian Stable, do not have patches available in the package repos, though they're being actively worked on.
Not true, if there’s any evidence of the exploit being used in the wild, it’s much more responsible to release immediately.
Considering that the patches have been available for a while, someone surely reversed what they were for and was actually exploiting this in the wild.
In the age of AI, I’d argue that “responsible disclosure” is dead. Arguably even in closed source projects. Just ask Claude to do a diff between the previous version and to see whether anything fixed in there could have had security implications.
We’re not there yet, but very soon the only way to responsibly disclose a vulnerability will be immediately.
But they didn't release immediately -- they waited a month, but forgot to tell the distros, and forgot to check if waiting a month had actually lead to distros picking up the patches and shipping them.
Which just reinforces my point. The patch was available, therefore, where the exploit lies was also available.
Linux kernel is one of the most audited open-source projects ever. I guarantee you that someone did reverse the patch.
> but forgot to tell the distros
Probably an oversight, but irrelevant. The bug was in the linux kernel. It's insane to suggest that they should have notified everyone shipping the linux kernel.
“Made it into the wild?” Patches landed a month ago. Should they also wait until my linksys router from 2018 has a patch ready?
Patches are still in the process of landing in most major distros as of the time of this writing. Most users are not able to get an update through their distro's packaging mechanisms.
It's a local vulnerability at least. How many people do you let log in to your router?
With the way linux is used these days, I'd guess the number of systems with untrusted local users is pretty limited. Even with shared hosting, you generally have root in your VM or container anyway. Unless this enables an escape from that?
Still the risk that people who run "curl | bash" without care could get bitten, but usually its "curl | sudo bash" anyway...
> Even with shared hosting, you generally have root in your VM or container
Lots of shared hosters don't use VMs or containers. It's some arbitrary number of people logging in to a shared system, each one with a home directory under /home/THE_USER_NAME. i've had several such hosters over the years (thankfully not right now, though).
> With the way linux is used these days, I'd guess the number of systems with untrusted local users is pretty limited
Things like HPC clusters are multiuser & don't entirely trust their users. If they did we wouldn't need users/groups/permissions etc in the first place.
Yes. Not even just HPC clusters, shared login servers are pretty common in academia. I manage several in our lab. Sure, we mostly trust the users against malice more or less but not so much against incompetence. A malicious vscode plugin would run rampant in this space.
And then there are users running claude-cli and friends who may just find it convenient to use a local root exploit to remove obstacles.
With this exploit it's trivial to jump from one container to another neighbor container. I've tried it and succeeded.
So containers don't protect you, only a VM.
So anyone pulling a malicious dockerfile jeopardizes the host? That would be bad...
...no shit? Why do you think people care about this issue?
> I've tried it and succeeded.
How so?
Local root is part of the path to escaping
That's mostly on Greg, a bit on the author.
Fedora is patched.
only for versions 6.19.12 & 6.18.22. older versions (which are used in distributions) are not ready yet.
I think it’s reasonable to expect folks in the security community who go to the trouble of creating a website detailing security vulnerabilities in specific listed software to pre-notify the security teams of that software. The CopyFail website calls out Ubuntu and Red Hat specifically, but apparently the author of the site did not inform them of the issue?
But even if you think making unethical decisions in personal self interest is something no one should be criticized for, surely the Linux kernel team ought to have some process for notifying the top distributions of an upcoming LPE, just out of practicality.
In what sense do you believe that the reporter did not notify the security team of the relevant software? The vulnerability is in the kernel. Reporter responsibly disclosed using the kernel’s security report mechanism and waited until a patch was ready.
Distros are downstream of kernel, that doesn’t entitle them to expect to be contacted directly by every security reporter. That’s not on them. Distros that are big enough should be plugged into the linux security team for notifications.
Security researchers cannot be held responsible for broken lines of communication within the org charts of projects that they study. They’re providing a valuable public service already, how much more do you want?
> that doesn’t entitle them to expect to be contacted directly by the reporter
Yes it does. That's how it's always been done and distros can ship a fix well before it ends up in a kernel release.
It is suggested that they out of an abundance of caution and 5 or 6 emails. If this is entirely to much to expect we can always help them by mandating that they spend 6 figures annually meeting a much more robust set of requirements that will include notifying all possible affected parties down to Hannah Montana Linux devs if any still exist.
Any strategy that assumes that the rest of the world is functional or makes you personally responsible for fixing all of it is equally broken but there is a reasonable middle ground and sending a few more emails lies within it
AWS and GCP are downstream another level. Should the reporter also have worked with them? And their customers? And the customers of their customers?
IMO this whole discussion seems like people are annoyed by the security researchers doing god’s work and wish they didn’t exist or think that they should be fully subservient to the projects and companies they are helping for free. The bugs were there before the researchers revealed them!!
> expecting people to always do the right thing is fantasy level thinking.
Most people in tech think like the techie in this comic strip.
https://xkcd.com/538/
The notification happen when the fix was shipped. That people would prefer to been spoon fed only serious security issues is understandable, but not realistic.
A large percentage of kernel fixes have the potential to be similarly bad. For some the potential isn't even realized until after the fix has shipped.
Ever stable release GregKH says you must upgrade now, because there is something security relevant in there. This happens at least once a week.
As for shared hosting providers it is my sense that there is always at least one local privilege escalation available to miscreants. Making shared hosting only safe if there is a certain amount of trust.
I remember bugs that were similarly bad from my university days 30+ years ago. Has anything substantially changed?
> Who knows how many shared hosting providers were hacked with this.
I'd consider a shared hoster which allows users to run their own (native) code and doesn't use VMs for tenant isolation extremely irresponsible in 2026.
This is probably more common than you think. VMs are expensive, both in resources and cost (if you’re using something commercial). OS-level isolation (shared kernel, cgroups, namespaces) is used pervasively
There are so many distributions that it is not possible to notify each one, unless there is some single distribution list for all.
And if you disclose to just a handful, why ignore the rest?
Who knows how many attackers had found this vulnerability and had already been using it prior to this research finding it?
Argument from uncertainty is not a good way to reason about this.
I could equally ask: "Who knows how many attackers learned about this vulnerability from this disclosure, and used it before the distributions fixed it?"
Yes, you could. Thats the core of my point: there is no Right way to handle vulnerability disclosure. There are many competing factors, most of them have major elements of uncertainty because you can’t know who knows what or how various projects or stakeholders will react.
So maybe folks should take a break from the kind of armchair quarterbacking that this was “incredibly irresponsible”, as was done upthread, or that the researchers should be blacklisted for life, as a parallel commenter stated.
well now everyone does, so the irresponsible disclosure makes it significantly worse.
It’s your opinion that it’s irresponsible and that it makes something worse.
and its your opinion that it doesn't. Shall we continue stating the obvious? We are communicating using glyphs. This language is English. We are on Hacker News. This branch of the conversation is extremely unproductive.
I asked a question and you replied with a statement. Your statement didn’t frame itself as an opinion but as fact.
The hilarious bit is that the idea that they needed to coordinate is clearly broken even in just this example. They did give prior notice to the Linux developers, who issued a patch. And they’re still getting raked over the coals in this comment page by armchair quarterbacks who have decided they needed to coordinate with specific distros. If they’d coordinated with those distros, somebody would have a pet distro that didn’t make the cut and they’d be pissed about that.
There are risks no matter how they do it, and there will be people who are pissed no matter how they do it. Security researchers don’t owe anybody a specific methodology.
you seemed to suggest with your initial statement that any disclosure was acceptable as people would have been using the exploit prior to the disclosure. I don't think that's a strong argument given now the initial people who were using the exploit prior to disclosure are now joined by people who have learned of the exploit as a consequence of the disclosure happening before all the distribtions were ready.
So I feel like the argument reduces into "why is it a problem that now anyone could exploit it, if some people were exploiting it already". Which imho isn't a sensible argument because the issue is clearly the amount of people capable of using the exploit for nefarious purposes, which has increased.
Idk why you felt the need to use quotes to wrap something I didn’t say, and that is a pretty uncharitable attempt at reframing my question. If you wanted a quote, here’s what I’d say:
“Because we can’t know if there was exploitation by existing parties who had discovered the vulnerability on their own, there are upsides to disclosing earlier so that affected users can take mitigating steps and review their systems for indicators of compromise. Additionally, the more projects the researchers pull into the loop for coordinated disclosure, the higher the likelihood that they further leak the vulnerability to more attackers.”
Idk why you felt the need to use quotes to wrap something I didn’t say. Despite the fact I didn't say that, its a much more interesting argument than your original statement implies and it is unfortunate we didn't start there.
However the issue is that we cannot know if the attack space has been broadened or lessened as a consequence of this disclosure, because of how eager it was. If it wasn't eager then we could much more comfortable in suggesting that the attack space has probably been reduced.
Given the exploit had been living in the linux code base undetected for so long in the first place, I think its fair to state that disclosing the exploit prior to the distributions being ready and given the distributions are the principal attack vector of the exploit: that the researcher has made the situation worse and should reflect on their actions.
… I used quotes to wrap something that I was saying. I even called out that it was something I was saying, as a more accurate variant of what you’d claimed I meant.
and I prefaced my quotes with the statement "So I feel like the argument reduces into". I mean, idk what punctuation I'm supposed to use there that doesn't offend you, but I just figured we can all read words and it was clear that I wasn't saying you said that, but rather, as I read the argument it was reducable to that and I took issue with that potential reduction.
The idea about the available exploit space and how the actors within it might, or might not move is a much more interesting avenue of conversation and I thank you for elaborating on your initial comment. <3
I do however feel that its hard to be confident about whether or not the attack space has been increased or reduced as a consequence of the eager disclosure. I feel we could make the case either way.
You could try to make that case either way, but as has been pointed out by others all over this thread, the system we've landed on (90/+30) is industry standard after over two and a half decades of experimentation.
Anything else inevitably has worse for the public good.
Having spent that entire time and then some on both offensive and defensive teams, I assure you longer delays after notification do NOT decrease the overall risk to the public.
There's a reason we've landed where we have as a security community.
The public disclosure page has a big blue "Get the exploit" button.
It's an advertisement for an unpatched critical exploit and apparently some kind of infosec company.
There is no such thing as irresponsible disclosure. Thanks though.
The title on this post was changed to imply that only the Gentoo developer was left out - which I could believe.
And now it was changed back. I'm goin' insane.
And now it's changed to be a generic "For Linux kernel vulnerabilities" rather than specifically about Copy-Fail.
Fundamentally.
The disclosure is private. Meaning neither the commit messages nor any public info can leak too much information about the bug. It's usually kept rather discrete.
It is impractical for the kernel to broadcast to all its users privately.
Meaning that either a) distro maintainers should be privy to it, but where does this end?[1] or b) we have the current situation
[1] probably the top 5 distros security teams can just be copied into the private mail. Maybe the kernel security private list can forward the emails to them as well.
Problem is, every other type of communication between distros and kernel is implicit. In commit messages, patches and release notes. So it's an exceptional case.
BTW, with LLMs there's a new issue. It is now cheap to scan the kernel commit log maybe in _next and ask it to identify what could be a patch for a private disclosure. And then immediately RE the patch and exploit it on deployed kernels.
> Who knows how many shared hosting providers were hacked with this.
None? Because nobody* does hosting using Linux users as a security boundary. It's not the 90s.
* Standard HN disclaimer for people that think that some retro shell box with 10 users disproves "nobody": nobody does not literally mean exactly 0 people in this context.
At least thankfully workaround is one line in a file.
“Shared hosting providers” These haven’t been a thing since VMs … basically for this reason. There’s always a local privilege exploit.
> “Shared hosting providers” These haven’t been a thing since VMs
That is unfortunately not true. i left my last one only a few years ago and they're still going strong without me.
> Anyway, this is a disaster. It was extremely irresponsible to share the exploit with the world before the distributions shipped the fix. Who knows how many shared hosting providers were hacked with this.
Maybe it is irresponsible how little attention we pay to software security. Maybe, software developers of all kind should spend an entire year not developing any features at all, but fix all the tech debt of 30 years instead.
Yes, that sounds revolutionary, but I do not see an alternative in an age where all you need to find kernel bugs of this scale with AI agents.
> It was extremely irresponsible to share the exploit with the world before the distributions shipped the fix.
It's a total arsehole'y move to not share with open-source projects (like Debian) but for commercial vendors like Microsoft I don't give a crap.
Now let's not get carried away either: that's a privilege escalation, so it already requires access to a local account. We're not exactly in Jia Tan "I backdoor every SSH out there if your Linux distro is using systemd" territory either.
>> Anyway, this is a disaster. It was extremely irresponsible to share the exploit with the world before the distributions shipped the fix.
Maybe a decade of corporations with revenue in the billions, paying peanuts and coffee money, for critical vulnerability disclosures made it....
> It was extremely irresponsible to share the exploit with the world before the distributions shipped the fix.
Yes, this was clearly a marketing stunt to promote Xint code.
I, for one, will never use Xint code and will advise everyone to never use it. To anyone working there: enjoy your 15 minutes, I hope this backfires right in your face.
I doubt it will and I hope it doesn't.
External security research happens for one of only a few reasons typically:
1) hobbyists who are learning or just like to do it for fun 2) bug bounties (good luck with those in most open source) 3) marketing for security companies 4) non-public research going to CNO/CNE
If you want to kill 3, the output of 1 will not come close to 4 and the public is NOT better off with fewer public bugs.
Counterpoint. End users have a right to mitigate this issue on their systems.
It is a really really bad look for Linux, puts a bit of water on all hype around switching from Windows.
It does? The disclosure even says the concern for single user systems is very low. If someone has access to your single user system, remote or otherwise, you’ve already lost on the sort of device people would be switching from windows to Linux on.
> The disclosure even says the concern for single user systems is very low.
For single user systems (not rigorously defined, I presume it's the intersection of our two definitions which we might be talking about) the nature of the exploit is local privilege escalation, of which there could be many possible, and many mitigations / countermeasures against. This could have suddenly appeared from the ether of "unknown unknowns" for some people.
Those people farther up the food chain still potentially have service accounts, maybe even user accounts for some purposes, perhaps "trusted" services which deliver them code which they deserialize and run once. (Have a pickle.)
severity * impact * likelihood
Not everyone looking to migrate from Windows 95 plans to run everything as root afterward.
On the copy.fail site:
Not everybody needs or wants to wait for their distro, or plans to patch their IC firmware when a config change will do.Someone like an AI coding agent perhaps ? This is the type of thing Prompt injection was made for.
No OS is perfect. The awkward rollout for this bug fix is proof of that.
Root access does not typically add anything interesting, for a desktop system. All the valuable stuff is already owned by the single user.
As opposed to all other operating systems with no CVEs ever?
Hype around switching from Windows servers?
What happens if someone does the exploit in WSL?
You clearly have no idea how often windows has unpatched privesc exploits.
>> puts a bit of water on all hype around switching from Windows.
Said no one ever...present post excluded :-))
> Note that for Linux kernel vulnerabilities, unless the reporter chooses to bring it to the linux-distros ML, there is no heads-up to distributions.
Why would they imply it is incumbent on the reporter to liaise with distributions? That seems to assume a high level of familiarity with the linux project. Vulnerability reporters shouldn’t be responsible for directly working with every downstream consumer of the linux kernel, what’s the limiting principal there? Should the reporter also be directly talking to all device manufacturers that use Linux on their machines?
IMO reporter did more than enough by responsibly disclosing it to linux and waiting for a patch to land.
Aren’t there people in the linux project itself with authority over and responsibility for security vulnerabilities? One would think they would be the ones notifying downstream distros…
Especially since the reporter is explicitly asked not to notify the distro teams first.
https://docs.kernel.org/process/security-bugs.html
```As such, the kernel security team strongly recommends that as a reporter of a potential security issue you DO NOT contact the “linux-distros” mailing list UNTIL a fix is accepted by the affected code’s maintainers and you have read the distros wiki page above and you fully understand the requirements that contacting “linux-distros” will impose on you and the kernel community. ```
> and you fully understand the requirements that contacting “linux-distros” will impose on you
Imposing requirements on the reporter? No.
I don't get why the initial reporter should have to do that legwork. The kernel maintainers should be doing that.
Ffs, we're talking about open source projects here. Those mailing lists, mentioned there, ARE PUBLIC.
Make them private? Now you have a nice stream of zero days, long before fixes are available, making bad actors who made it in filthy rich.
There are a zillion of distributions. The mailing list at https://oss-security.openwall.org/wiki/mailing-lists/distros includes some I never heard about and misses some famous ones (Mint, POP OS.)
The bug is in the kernel, so it's OK to notify only the kernel team. Then they should notify the distributions they are in contact with.
The first message about Copy Fail that I see in the archive https://www.openwall.com/lists/oss-security/2026/04/ is from April 29. I run apt on my Debian 13 yesterday and got the fixed kernel.
Do I expect that every distribution is already patched? I don't. However each of us choose the distribution to run. Security can be one of the criteria for the choice. I played safe and I'm using Debian. Other people can make a different tradeoff maybe based on their personal threat analysis.
There are people running end of life kernels and distributions in production, or with pinned old kernels especially on ARM SBCs. I know both. Those are other choices made at the user end of the process.
IMHO the disclosure and fix process was run in the proper way from the researcher to the end user.
The kernel team has been at odds with the CVE process and the oss-security community about this stuff for many, many years now. It's a big part of why the kernel team established a CNA and started flooding CVE notifications; they don't believe that security problems are different than non-security problems, and refuse to establish norms or policies based on the idea that they are.
> […] they don't believe that security problems are different than non-security problems, and refuse to establish norms or policies based on the idea that they are.
They believe there is no difference being able to get root and not being able to get root? It seems to me that to-be(-root) and not-to-be(-root) are quite different.
No, they believe that almost all bugs in an operating system kernel are also likely to be security bugs. The ones which get domain names, POC exploits, and CVE assignments are the ones which were found by security researchers. But the bugs that get found and fixed by kernel developers regularly without fanfare are also very likely to be exploitable. It's just that nobody took the time to cook up an exploit chain. To kernel maintainers, it's silly to assign CVEs to just some of the likely exploitable bugs just because a security firm found them. So they decided to take the reigns and handle CVEs themselves, to ensure all potentially exploitable bugs are marked as such.
It's such a bizarre viewpoint. I wonder when Linus will see sense.
IMO it's pretty obviously not a view that they seriously hold, it's just one of those technical justifications people come up with to avoid admitting something they don't want to admit - in this case that Linux has a poor security track record.
Linus? You mean, the same Linus who thinks "security people are f*cking morons", and "security bugs are just bugs"?
Linus is the reason why kernel team doesn't talk to distros. For them bugs are bugs, security related or not.
https://lkml.iu.edu/hypermail/linux/kernel/1711.2/01701.html...
I think it's an extension of the premise that you should just be taking the whole stable tree with all its patches constantly, whether they're labeled as security fixes or not, because you can never really know for sure some bugs weren't security bugs.
I don't agree with the premise, but I do think it's a sincerely held one.
The kernel begrudgingly admitted of the existence of LTS releases, they really don't like long-lived kernels and people not tracking at or near the latest release.
I dunno, if you think about it for more than a few seconds you can see the obvious holes in it, like it's definitely true that some bugs are "may allow RCE", but you also can do a LOT better than not even trying. And even if you do say "we're not putting the effort in to backport security fixes" (which is fine), that doesn't entail "security bugs are just bugs".
These are smart people. If it wasn't about their own project I really think they'd have a different point of view. I wonder what they say about Microsoft's security bugs for example!
> I wonder when Linus will see sense.
Literally never. Why would he? He's surrounded by sycophants. And we have Greg for whenever Linus isn't involved anymore, and Greg is just as boneheaded.
The reporter took time to check and mention on their website specific distributions Ubuntu/RHEL/SUSE. One would have thought reporting to security teams of at least those would be responsible.
“One” would have thought? Can you point to a written policy that says that’s how it should be?
No, nor can I point to a written policy that states one should cover one’s mouth when they cough.
Everyone involved here failed to do the right thing, and hiding behind the lack of written words is weak sauce.
The tenets of decency don’t need to be written down.
If you can't write it down, why would you expect it to be universal and enforceable? Different cultures exist and have different opinions on what "decency' means, after all.
A security researcher's ethical obligations are to protect users over vendors (barring any contractual agreement in place). From what has been discussed in this thread, they meet that bar.
Sure, they could have gone the extra mile to ensure the distros were in a good place to patch before they published the exploit. That's a kindness you can wish for, but don't disparage them for not going that extra mile. It's a bonus.
It's also possible that it simply didn't occur to them to do so this time. There's certainly lessons to be learned either way. I don't know that the right lessons will emerge from hostility.
> If you can't write it down, why would you expect it to be universal and enforceable?
and this is the problem. It used to be the case that if you were smart enough to find an exploit you were also smart enough to realise what would happen if you irresponsibly disclosed it. I guess these tools have made that pattern no longer apply.
From my point of view, they told the kernel security team which is in charge of fixing this. If it’s important for them to tell other people, then it should’ve been written down and further reiterated when they made their report.
The skills to detect code exploits is not the same as the skills to navigate an informal org chart to the satisfaction of an amorphous audience if end users (i.e. us on HN).
That said… as they are a company that supposedly specializes in this field, and is trying to sell a product, I do believe they should do better. Right now, I don’t have much confidence in their product.
different cultures have different views on disclosing vulnerabilities to distros before the public?
Yes :) The blackhatter would obviously sit on it until they can sell it or use it, the whitehatter collaborate the kernel and distros to patch, and the greyhatter argues on HN whether the latest *fail was responsible enough or not.
Yes? "Different cultures" doesn't just mean different countries; there are many cultures within infosec.
There is little difference in culture here. Nearly all open source work is done in English.
The reporter made a website explicitly calling out Ubuntu, RedHat, Amazon, and SUSE but didn’t notify them, and you think that’s reasonable? That they might not have known those distributions are downstream from the kernel team?
If you notify the kernel and they ship a fix, it seems reasonable to expect that they will communicate the fix to the distros.
I see this as an organizational failure of the Linux ecosystem. There should be better communication between distro and kernel development.
The reporter clearly knows the distro fixes have not been shipped, read their report. They chose to disclose anyway.
>They chose to disclose anyway.
yes, because 30 days had passed from the time the patch landed in the kernel, as per industry standard.
approximately every security researcher, including the likes of google and other big names you may know, does a 90+30 disclosure, which is what happened here. they do this for good reason, which has been figured out over decades of experience in reporting thousands and thousands of vulnerabilities.
the only security researchers i know of that dont like 90+30 actually argue for shorter timelines (or immediate disclosures).
What is the heuristic for who should get the heads up? Should they notify amazon but not google simply because they named amazon linux in the report? Seems to me the answer to my first question gets messy fast.
Sure, maybe it's not a _requirement_, but now we're all in more pain because the reporters are more interested in Fame than Safe Remediation.
No, you're in more pain, but other defenders with different postures benefit from having faster and fuller disclosure.
Mind explaining how sitting on it a month after the patch landed is 'faster'? To my mind, that's a month where attackers could analyze commit logs, but maintainers are not acting with urgency to ship fixes.
No, I wouldn't, because my own preferences are towards immediate disclosure. Tavis Ormandy dropped Zenbleed out of the sky onto us. It wasn't comfortable, it was a scramble for us, but I don't blame Tavis for it; he made a principled call. Better that people know, than that information be concealed from them while designated elites perform a process.
I'd also prefer immediate disclosure, but I don't get how waiting a month without telling anyone is good regardless of which side you land on.
>I'd also prefer immediate disclosure
wait, what?
you are in another comment thread, of this very post, calling these reporters bumbling and incompetent for their disclosure. "merely bumblingly incompetent and overly eager to get their marketing pitch out the door" - that is your quote.
you also said "Basic care would involve making sure the patches had made it into the wild before ending the embargo", which is the literal opposite of immediate disclosure.
but now you are saying they should have just dropped it with no reporting at all? because that is what "immediate disclosure" means. pop up the exploit script on twitter and call it done.
Yes, if you release the vulnerability as soon as possible, that's a good choice. If you have an embargo and make sure that fixes get out to users in a timely manner before ending the embargo, that's also a reasonable choice.
If you're going wait a month between landing the patch (possibly notifying attackers), but not notify the people who may get the patch to users, it seems like something was mishandled.
> No, you're in more pain, but other defenders with different postures benefit from having faster and fuller disclosure.
Good for them. But just because some folks cannot afford 24/7 response teams and on-call personnel that doesn't make them or their systems any less important.
Lots of non-profits and academic institutions had to scramble because of the Linux kernel team's position of non-communication to distros.
The conversation about how Linux handle these things is a good and worthy one to have and one "non-profits and academic institutions" need to have when they select distributions. I'm just here to push any of that scrutiny off the vulnerability reporters; Linux is lucky to have them, even if it's mishandling their reports. Vulnerability researchers don't owe these people anything.
it's trivial to find out how to report a security issue like this to Linux distros.
Google search: https://share.google/aimode/eihDKXZJy94Z5lC1p
and it's beyond me to not think about doing this and instead exposing everyone and their neighbor to this exploit up front.
I'm certain this is even a felony in some legislations, rightfully so.
Agree it's not a good look for these folks, notwithstanding that disclosure is mostly theater.
Unrelated but also a CVE that popped up for ProFTPd: https://www.openwall.com/lists/oss-security/2026/05/01/4
What's interesting is that their website is also down right now. These seem like special-timed DDos attacks so maintainers cannot communicate the issue well.
I suspect there are very few real setups affected by that proftpd bug.
Nobody is ddosing anything to cover it up.
The most interesting exchange, related to disclosure, is this one:
https://www.openwall.com/lists/oss-security/2026/05/01/3
> Nope, sorry, we are NOT allowed to notify anyone about anything "ahead of time" otherwise we will have to tell everyone about everything. That's the only policy by which all the legal/governmental agencies have agreed to allow us to operate in, so we are stuck with it.
greg k-h
As much as I like linux, this is stupid.
Stop blaming the reporter. Start asking kernel to fix their process. Linux kernel is no longer a toy project, it has full time employees employed by various companies. They should have handled notifying distributions. Not some rando.
Look, if they namedrop specific distros in their announcement (marketing) blog post as affected, I think a heads-up before publishing that is appropriate and expected.
I don't think they would have gotten as much flame if it weren't for how the RHEL 14 mention and such were put.
This is a security company with a professional(?) communications department banking on pointing fingers at distro maintainers. We are not talking about solo security researchers or academics here.
Exactly. Any security person absolutely KNOWS that the distros are still going to be vulnerable. They're exploiting this process loophole to knowingly cause chaos and gain notoriety.
At this point this is not really white-hat/ethical hacking anymore.
Ofc the kernel-distro security loophole is stupid and should be patched ASAP, but that doesn't absolve this company of wrongdoing.
Linus should take his trademark autistic rage where he calls other peoples code "dogshit" onto his own work for once. He likes the glory of leading the kernel development but not the responsibilitys like this.
No, I will. The distros and the kernel devs should be talking and moving on high sev patches, sure. But real people will have gotten hurt because the reporter didn't want to wait for that to happen. That's on them.
you must be unfamiliar what used to happen before hard deadlines were set on disclosure. it was much worse for the users.
here is a good start: https://projectzero.google/vulnerability-disclosure-faq.html...
there is ~3 decades of more context if you search for it.
tldr: if security issues don’t get disclosed (or the real threat of disclosure) they won’t get fixed / prioritized.
It's one thing to report a vulnerability, another entirely to make a crazy exploit available for any tom, dick, and harry to take and use. It was irresponsible of whoever came up with it to release it in the world without first giving major distros a head's up.
Bashing on the reporter is pointless feel-good. This is a massive vuln. It was 4 weeks after Kernel had a patch. They had no way to know if others parties had also discovered the vuln. Lord Knows how many millions of systems could already have been rooted. The reporter is not their minion.
If I call 911 to report a fire at an oil storage facility - and they ask me to alert the hospital, then phone the neighboring county's Sheriff Dept., and then...yeah. Either I'm way out in the sticks (and known to/trusted by the 911 operator), or else the 911 service is run by children.
Great metaphor.
I'd hate to be involved in any emergency services. Too many people have opinions on how things should have been done.
Just for what it's worth, I just pushed an eBPF-based workaround for people who are running kernels in which AF_ALG is linked directly into the kernel and not as a module: https://github.com/Dabbleam/CVE-2026-31431-mitigation
I am running this in production right now and it mitigates the attack, with no unexpected side-effects as far as I can see.
Interesting comment by Greg Kroah-Hartman when asked why the kernel team doesn't notify distros directly
> Nope, sorry, we are NOT allowed to notify anyone about anything "ahead of time" otherwise we will have to tell everyone about everything. That's the only policy by which all the legal/governmental agencies have agreed to allow us to operate in, so we are stuck with it.
I'd be interested in knowing more about that policy... Seems that there should be exceptions for the major distros.
Of course, major distros who have contracts with SLA could also pay for someone to be on the kernel security team and get a heads up like that..
The members of the kernel security team are not allowed to tell their employers anything that happens on the security list. They are there as individual members, not as employees.
And try to define "major distros" in a way that actually means anything viable.
If you just want to count users, then that would only be Android (everything else is a rounding error.) After Android, that would be Yocto, and then Debian. All distros after that are mere fractions of overall users compared to those 3 by number of running systems alone.
If you want to count it as "$ spent on Linux" then that cuts out Android and Yocto and Debian as those distros are free, and would focus purely on the tiny installed base of paid Linux systems, and cut everyone else out.
So what is a fair way to do this other than "we notify no one, and tell everyone to always update their systems to the latest stable releases that we support."
Especially as there is no way for us to determine your use case (i.e. if a specific bug is a vulnerability for you or not.)
`nosuid` and probably `nodev` should IMO be the default filesystem mount options. `/dev` is already a special devtmpfs and the initrd minimal /dev can just explicitly mount the initrd tmpfs rootfs with `dev` and `suid` if necessary.
Letting SUID binaries just "exist" anywhere is a stupendous security issue. What if you mount some external storage medium, how are you to verify that none of the SUID binaries on that block device are malicious.
Additionally, this exploit appears to only work if the user executing the SUID binary can also read the SUID binary. There's no reason for non-root users to have read on a SUID binary.
NixOS does this correctly. No SUID in the normal package installation directory `/nix/store` and no package leakage outside of that no `nosuid` can safety be used on all other mountpoints. The exception is just a single-purpose `/run/wrappers.$hash` directory that safety contains executable ONLY SUID wrappers.
While I hate suid as much as the next person, it's really not the problem here.
The bug that is being exploited gives you basically arbitrary page cache poisoning. At that point it's already game over. Patching a suid program is maybe the easiest way to get a root shell from that but far from the only.
The proof of concept exploit is just that. It is meant to demonstrate one attack vector only. There are many others. If your goal is to prevent the conceptual exploit only then there are many easier ways to accomplish that, such as blacklisting, that does not make you safer.
With this vulnerability you can manipulate the page cache. You could also manipulate ld.so to hook into arbitraty system calls, or set your uid to 0, or any of another dozen or so ways to elevate your privileges.
Mount points have nothing to do with this, even if is always a good idea to disallow suid in user writable areas and prevent reading suid files, but that's for other reasons. NixOS does nothing to fix this and is just as vulnerable as everyone else.
Without read permissions you cannot execute the binary, that would not make any sense.
To execute the binary it needs to be read from disk and loaded into memory.
In fact if you have read permissions but not executable permissions on a specific binary then you can still execute it by calling the linker directly /bin/ld.so.1 /path/to/binary (the linker will read and load the binary and then jump to the entry point without an exec() call)
> Without read permissions you cannot execute the binary
This is not correct, as when the binary is setuid-someone-else, you are not the one executing it; they are.
Removing world-readability from all setuid-root binaries on the system would be sufficient to kill the PoC script provided for this vulnerability. It would not be sufficient to prevent exploitation though; there are many ways to abuse the ability to write to files you have read access to in order to gain root, for example by using the vulnerability to alter the cached copy of a file in /etc/sudoers.d/, or overwrite /etc/passwd, or /etc/crontab, ... the list goes on.interesting but in that case no point in keeping the x bit either and suid binaries should just be 4700 ?
If they don't have world-execute permission, an access(2) check for executability would return negative, leading to things like shells not tab-completing it. The kernel would also deny attempting to execute it, as it is not executable for your fsuid.
You need execute access in order to launch it, but in order for it to run, the user it is running as (not you) needs read access; you don't.this ld.so magic will lose the suid bit
loader
The Bleeping Computer link below mentions a potential remedy until a patch is ready.
https://www.bleepingcomputer.com/news/security/new-linux-cop...
This workaround only applies to kernels with the impacted code compiled as a module. RHEL, Fedora, and Gentoo (we use a modified Fedora config) all are configured to build this in directly. Without a patch or config change (as Sam from Gentoo was alluding to), those distributions remain vulnerable.
There was some discussion on the GitHub issues about workarounds to disable it, even though it is baked in.
https://github.com/theori-io/copy-fail-CVE-2026-31431/issues...
https://github.com/theori-io/copy-fail-CVE-2026-31431/issues...
This worked as a mitigation on distros with the module compiled into the kernel: https://gist.github.com/m3nu/c19269ef4fd6fa53b03eb388f77464d...
Basically: sudo grubby --update-kernel=ALL --args=initcall_blacklist=algif_aead_init
sudo reboot
F44 is safe as the kernel is greater than 6.18.22
For compiled-in kernels you can also work around it without rebooting via apparmor, seccomp or SELinux at the least, there may be eBPF or other methods too.
The potential remedy doesn't work on RedHat and derivatives because the affected code is not a module there but statically compiled in.
Neither was NixOS.
https://discourse.nixos.org/t/is-nixos-affected-by-copy-fail...
None of the distros were.
Ubuntu has patches out, tested before and after patching.
Related:
Copy Fail
https://news.ycombinator.com/item?id=47952181
`initcall_blacklist` is a thing.
Was not disclosed to stagex, and I expect a lot of linux distros. Thankfully we were already on kernel 7.0 so not impacted
Welcome to AI first world, everything is about fail and repriced.
I believe this is the side effect of having upstream manage the CVE process.
The distros dont get any involvement until release, welcome to the suck.
Seems silly. How many distros need to be notified? There are hundreds.
That is true, but if at least the widely used ones would get notified before that would be beneficial. If they have a responsible security contact point.
- Debian
- Ubuntu
- Arch
- Amazon/Azure
- Fedora/RHEL
Then the ones that aren't notified will complain. I think it's on the distros to follow kernel developments since they are consumers of the kernel, not the other way around. Kernel devs can't possibly know all of the users they need to notify.
Hyperbola GNU was save because they still use Python 3.8 for both political and stable reasons.
Python 3.10 is only used for the exploit. You can easily rewrite it for 3.8 as well. The vulnerability itself does not require Python at all.
huh somehow seeing people not using ai to work is like wow moment which i cherish a lot these days
You're likely in an echo chamber! Barely anyone I know uses AI as more than a fallible tool.
I blame X for this. I don't use it, but whenever I open the feed I get bombarded with bullshit that is packaged like a unicorn.
Hey Xint Code / tylerni7 <https://news.ycombinator.com/threads?id=tylerni7>, maybe you should improve your disclosure process as well? Maybe make it mandatory for users of your tool?
they disclosed 30 days after the patch was merged in the thing they reported to.
its the same disclosure policy as google's project zero, and several other major players, so you should probably be trying to ping a lot more people
reporters should not be responsible for finding out and individually reporting to every downstream consumer. blame the kernel security team, who is in a much better position to coordinate notifications to individual distro security teams.
In the original thread they admitted multiple times that they rushed it out for marketing reasons.
as an explanation for the misnumbered redhat version.
the disclosure itself followed a normal timeline, which you can view at the bottom of their blog post.
The security research community would run you out on a rail if you tried to take a successful research product and attach mandatory disclosure norms to it.
Couldn't the product itself disclose to the vendors?
No firm in the world would use a vulnerability research product that automatically disclosed to vendors.
I have checked all the servers (bookworm, bullseye) that I manage, and none of them have the algif_aead module loaded.
Seems not fatal to all non-patched systems.
Not having the module loaded doesn't mean you're not vulnerable, the kernel loads the module on-demand when it's needed. I tried the exploit on such a system, and it worked.
However, not having the module loaded does mean that in normal operation you don't need the module, so the proposed mitigation of disabling the module is safe in the sense that it won't disrupt anything.
I don't know what exactly can load this module but the servers are running for many weeks and I suppose that if something will load this module, it stays loaded until the next reboot.. no ?
I tried to rmmod on all servers and rmmod always returns `ERROR: Module algif_aead is not currently loaded`, that's why I think it's fine. Of course I take a look on https://security-tracker.debian.org/tracker/CVE-2026-31431 for the updates.
> I don't know what exactly can load this module
Well, for one thing, opening an AF_ALG socket, as the exploit does.
rmmod just tells you it's not loaded; you'd have to delete the module to prevent it auto-loading.
> I have checked all the servers (bookworm, bullseye) that I manage, and none of them have the algif_aead module loaded.
But only Trixie (and testing/Sid) are patched (as I type this).
On Bookworm (and Bullseye), you want to add the module to list of blocked modules. It's a one-line change.