Yet another critical vulnerability in systemd, this time involving snapd. Ubuntu folk are affected.
“A serious security issue has been discovered in Ubuntu, and it is gaining attention in the cybersecurity community. The vulnerability is identified as CVE-2026-3888 and mainly affects Ubuntu Desktop systems from version 24.04 onwards. This flaw is dangerous because it allows an attacker with limited access to gain full root privileges. Root access means complete control over the entire system.”
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
/tmpis 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.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 upgradedid 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 availableedit:
i triedsudo apt install snapdbut 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
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…?
Yes, thank you for the extra info!
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.Yet another critical vulnerability in the much vaunted systemd has been exposed by a misbehaving app - in this case snapd.
Both need patching.
No Dylan, don’t bother fixing this shit, go straight for the boot licking commit.
go straight for the
/bootlicking commitFTFY
Snap back to reality
