[xeeeeeeeeeeenu]

It seems there was some kind of confusion during the disclosure process, because the vendors aren't treating this vulnerability as serious and it remains unpatched in many distros.

https://access.redhat.com/security/cve/cve-2026-31431 "Moderate severity", "Fix deferred"

https://security-tracker.debian.org/tracker/CVE-2026-31431

https://ubuntu.com/security/CVE-2026-31431

https://www.suse.com/security/cve/CVE-2026-31431.html

[MarleTangible]

Seems like distros consider it a medium risk because it doesn't involve remote code execution and requires local access. Though it allows local root privilege escalation which is considered high priority.

https://ubuntu.com/security/cves/about#priority

> Medium: A significant problem, typically exploitable for many users. Includes network daemon denial of service, cross-site scripting, and gaining user privileges.

[oskarkk]

Strange that it's not classified as "high", which specifically includes "local root privilege escalations".

> High: A significant problem, typically exploitable for nearly all users in a default installation of Ubuntu. Includes serious remote denial of service, local root privilege escalations, local data theft, and data loss.

[amarant]

It is high now, someone at canonical is paying attention it seems

[markhahn]

if your model is that linux is just about single-user desktops, this local exploit isn't too bad. or if your model is nothing but DB servers or the like.

mystifying to me that shared, multi-user machines are not thought of. for instance, I administer a system with 27k users - people who can login. even if only 1/10,000 of them are curious/malicious/compromised, we (Canadian national research HPC systems) are at risk. yes, this is somewhat uncommon these days, when shell access is not the norm.

but consider the very common sort of shared hosting environment: they typically provide something like plesk to interface to shared machines with no particular isolation. can you (as a website owner or 0wner) convince wordpress/etc to drop and execute a script? yep.

[CGamesPlay]

> if your model is that linux is just about single-user desktops, this local exploit isn't too bad.

For example, if you have passwordless sudo, you've already got a widely known LPE vulnerability lurking on your system.

[dwedge]

Only for your user, and it means a keylogger on the system if it gets rooted can't pull your password to try on other machines. Personally I always either login as root or use passwordless sudo.

[XorNot]

Yubikeys are also surprisingly annoying when setup for the as well. A working developer just needs sudo a lot.

Realistically a "sudo button" would be handy, on the keyboard, with a display to show a confirmation pin for the request (probably also needs a deny button so you can try and identify weird ones).

[parliament32]

Sounds like a good use case for that new Copilot button you see on newer keyboards.

[IshKebab]

You don't even need a button. Just a secure dialog like Windows has.

[Pay08]

I mean, that's what you have pinentry for.

[oviet]

hmm have i missed anything?

[OvervCW]

Any program on your computer can just run "sudo" to escalate itself.

[hk__2]

The problem is not the passwordless sudo but running untrusted programs on your computer under your user. They don’t need sudo to steal your SSH keys or inject malicious code in your .bashrc.

[AntiUSAbah]

Not to bad? So we just threat linux overall as a single user system or what?

[edelbitter]

Ubuntu is not really targeting multi-user any more. Security update installation is deliberately delayed for all users, until at some point all unprivileged users ended all processes launched from the vulnerable snap image. (Firefox RPC breaks when you replace the binary, so having to reopen your browser to keep opening tabs simple because security upgrades were applied in the background would be inconvenient)

[daveoc64]

Ubuntu seems to have updated the page to say that it's a high priority now.

[mghackerlady]

it's not like this couldn't be chained with some other exploit to get remote access to get remote root access which seems like a bit of an issue

[dwedge]

Local access is a bit of a misnomer though, a vulnerable website can be tricked into running a script

[xmcqdpt2]

True but that requires another vulnerability.

It's security in depth. You build your server in a way that it doesn't allow remote code execution, and then you run it with an unprivileged user so that if it does allow it, the consequences are limited. And if running arbitrary code is a feature (you are github or whatever) you use VMs.

[staticassertion]

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).

[still_grokking]

Will this continue like that even when the prophesied Mythos Vulnocalypse hits the Kernel?

This stance doesn't seem sustainable any more to me.

[staticassertion]

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.

[still_grokking]

How about SELinux, like on Android?

[nromiun]

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.

[staticassertion]

The specific exploit payload for the POC relies on a su binary. The vuln is ambivalent and other non-su paths will exist.

[staticassertion]

I assume that wouldn't help here but I could easily be wrong. (Assuming if you're asking if SELinux would block this exploit).

[fuomag9]

selinux on enforcement mode did not mitigate the exploit when I tested today on fedora coreos :(

[stefanor]

As far as we can tell, nobody disclosed it to the distributions, only to the kernel security team (who did not reach out to distributions). So the distributions are all scrambling now.

Good lesson in how not to do disclosure.

[baggy_trough]

Why wouldn't the kernel security team reach out to distributions?

[stefanor]

The Linux project's view is that almost all kernel bugs are security vulnerabilities. They don't treat something like this as anything special.

I can understand that PoV, but it doesn't fit with distributions' approach to security. So, in practice, one has to reach out to distributions individually, or use distros lists on openwall.org to coordinate with all distros.

[wangman]

RedHat has also changed it to "Important severity" and "Affected" now.

[DooMMasteR]

Yeah, it was also staged for release on the affected kernel branches a while ago, but almost all still had the window open and only tonight got the merged across all maintained kernel versions.

It's not good... and surely not "responsible/planned" disclosure.

[AntiUSAbah]

I'm schocked that ubuntu is aware of this and the prv lts is not patched yet :|

wtf

[Yokohiii]

upgraded today and they've put the kernel module install override in place. (wsl2/ubuntu)

[Tuna-Fish]

Yeah, by ubuntu's own guidelines linked on that page, this should be priority: high, but instead it's marked as medium.

[no-name-here]

That was fixed, it’s now marked high.

[Neil44]

I thought that. surely people are going crazy right now owning anything with an our of date Wordpress exposed.

[baggy_trough]

The upstream stable kernels (6.12.85, etc.) are out now with the fixes.