This is not a systemd flaw. This is a snap bug.
e:f;b
this post was submitted on 01 Apr 2026
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Yet another critical vulnerability in systemd
This is a critical vulnerability in snapd, not systemd. It sounds like it could also be exploited if something other than systemd deleted the files in /tmp/. Or if /tmp/ was not mounted.
Is it possible they mean both snapd the program and sysd the project have a vulnerability? Is snapd built by sysd, or more of like a ubuntu extension of the sysd ecosystem that they've built themselves?
Snap is Canonical's project AFAIK
snap
well there's your problem
Not a very good article. The original write-up (not linked anywhere in the article) is here: https://blog.qualys.com/vulnerabilities-threat-research/2026/03/17/cve-2026-3888-important-snap-flaw-enables-local-privilege-escalation-to-root
They also mention something else that's interesting at the bottom of the write-up:
Secondary Finding: Vulnerability in Ubuntu 25.10 uutils Coreutils
In a proactive security effort prior to the release of Ubuntu Desktop 25.10, the Qualys Threat Research Unit assisted the Ubuntu Security Team in reviewing the uutils coreutils package (a Rust rewrite of standard GNU utilities).
A race condition in the rm utility allowed an unprivileged local attacker to replace directory entries with symlinks during root-owned cron executions (specifically /etc/cron.daily/apport). Successful exploitation could lead to arbitrary file deletion as root or further privilege escalation by targeting snap sandbox directories.
The vulnerability was reported and mitigated prior to the public release of Ubuntu 25.10. The default rm command in Ubuntu 25.10 was reverted to GNU coreutils to mitigate this risk immediately. Upstream fixes have since been applied to the uutils repository.
Wait. So the flaw was in uutils, and this article reported it as a systemd bug...?
And, even further: a rust implementation vulnerability too?
(Waits for C vs Rust war to start...)
Yes, thank you for the extra info!
No Dylan, don't bother fixing this shit, go straight for the boot licking commit.
go straight for the
/bootlicking commit
FTFY
from adding an age field to fixing snap, the guy does it all!
When I need to create scratch files I usually operate in /tmp. Almost all directories there that I saw were using randomized paths (e.g. UUIDs). I guess this is to prevent problems mentioned in the article. So, I believe this would be a vulnerability of snap, not systemd.
I use Fedora where /tmp is created as tmpfs, which lives in RAM and is cleared when the system is shut down. I wonder what's the benefit of Ubuntu's approach.
If you think about it for even a minute this is still a glaring cve in systemd, exposed in this case, by misbehaving snapd. systemd still needed to be patched and so did snapd.
Ubuntu configures systemd-tmpfiles to delete a snapd tmp dir, snapd runs setuid root and blindly trusts/executes files from a tmp dir it does not manage the life cycle of. Where is the flaw in systemd here?
I don't see how systemd is in wrong here. Curious, what would you change about it?
how would i know if Kubuntu 25.10 is affected (based on ubuntu)?
i guess this means yes?
command 'snap' from deb snapd (2.73+ubuntu25.10.1)
as it is lower than the version mentioned in the article "Upstream snapd: versions prior to 2.75"
now the question is how do i force an update on that thing?
sudo apt upgrade did not include an update for snapd:
Upgrading:
bpftool linux-headers-generic linux-libc-dev linux-tools-common
linux-generic linux-image-generic linux-perfInstalling dependencies:
linux-headers-6.17.0-20 linux-image-6.17.0-20-generic linux-tools-6.17.0-20
linux-headers-6.17.0-20-generic linux-modules-6.17.0-20-generic linux-tools-6.17.0-20-genericSuggested packages:
linux-toolsNot upgrading yet due to phasing:
fwupd libfwupd3Summary:
Upgrading: 7, Installing: 6, Removing: 0, Not Upgrading: 2
Download size: 212 MB
Space needed: 421 MB / 417 GB available
edit:
i tried sudo apt install snapd but it returned:
snapd is already the newest version (2.73+ubuntu25.10.1).
snapd set to manually installed.
edit2:
or am i save because of this?:
Ubuntu 25.10 LTS: snapd versions prior to 2.73+ubuntu25.10.1
Switch to Devuan and have a peaceful life I guess.
Cheers!
"Systemd is built badly by weaponized dunning-kruger" -- pros
exploit [happens]
World: surprised pikachu
Snap back to reality