Re:Copy Fail – CVE-2026-31431
by staticassertion on Wednesday April 29, 2026 @08:31PM
(#47956515)
It was already known to attackers (or basically anyone watching) weeks ago when the patch hit the kernel but it wasn't communicated by upstream as a vuln (because Linus and Greg do not believe that vulnerabilities are conceptually relevant to the kernel).
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Re:Copy Fail – CVE-2026-31431
by still_grokking on Wednesday April 29, 2026 @08:46PM
(#47956655)
Will this continue like that even when the prophesied Mythos Vulnocalypse hits the Kernel?
This stance doesn't seem sustainable any more to me.
Re:Copy Fail – CVE-2026-31431
by staticassertion on Wednesday April 29, 2026 @08:48PM
(#47956673)
The response from Greg was that Mythos proved that upstream was right all along and that they'll continue to do things the same way. That's my recollection, at least - pretty sure it was something like that, could have been even worse though and I'm misremembering.
The stance was never sustainable, hence linux LPEs being constantly available. The solution is to treat your kernel as impossible to secure. Notably, gvisor users are not impacted by this CVE. Seccomp also kills this CVE.
Re:Copy Fail – CVE-2026-31431
by still_grokking on Wednesday April 29, 2026 @08:53PM
(#47956709)
How about SELinux, like on Android?
Re:Copy Fail – CVE-2026-31431
by staticassertion on Wednesday April 29, 2026 @09:34PM
(#47957008)
I assume that wouldn't help here but I could easily be wrong. (Assuming if you're asking if SELinux would block this exploit).
To even get the su binary on Android you have to patch the OS. So this exploit can't work on Android. Because there is no su binary to target.
Update: Just tried it on Termux and as expected even creating an AF_ALG socket requires root access.
Re:Copy Fail – CVE-2026-31431
by staticassertion on Thursday April 30, 2026 @05:12AM
(#47960011)
The specific exploit payload for the POC relies on a su binary. The vuln is ambivalent and other non-su paths will exist.
Of course, but it does not matter as the entire AF_ALG module is forbidden by SELinux anyway (on Android).
Re:Copy Fail – CVE-2026-31431
by staticassertion on Thursday April 30, 2026 @11:08AM
(#47963684)
That's fine and a very separate reason why it would not be exploitable, also assuming that the module is not just compiled in since then loading it would be irrelevant.