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Recent: Copy Fail - https://news.ycombinator.com/item?id=47952181 - April 2026 (466 comments)
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Discussion (173 Comments)Read Original on HackerNews
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.
> 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'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 that they would during the right thing, hence why it's a bad thing to rely on.
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.
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?
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...
What’s your theory here? What crime?
It's fundamentally their position to not work the way that you describe.
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).
Maybe a decade of corporations of revenue in the billions, paying peanuts and coffee money, for critical vulnerability disclosures made it....
It is a really really bad look for Linux, puts a bit of water on all hype around switching from Windows.
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.
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…
Everyone involved here failed to do the right thing, and hiding behind the lack of written words is weak sauce.
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.
I am running this in production right now and it mitigates the attack, with no unexpected side-effects as far as I can see.
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.
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.
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.
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)
https://discourse.nixos.org/t/is-nixos-affected-by-copy-fail...
https://www.bleepingcomputer.com/news/security/new-linux-cop...
https://github.com/theori-io/copy-fail-CVE-2026-31431/issues...
https://github.com/theori-io/copy-fail-CVE-2026-31431/issues...
Basically: sudo grubby --update-kernel=ALL --args=initcall_blacklist=algif_aead_init
sudo reboot
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.
Copy Fail
https://news.ycombinator.com/item?id=47952181