CVE-2026-53612

Name	CVE-2026-53612
Description	util-linux is a random collection of Linux utilities. In util-linux 2.39 through 2.41.4 and 2.42 through 2.42.1, the SUID `mount` utility's `hook_owner.c` post-mount hook performs path-based `chmod()` and `lchown()` operations on a previously validated mount target. A local low-privileged user authorized by an `/etc/fstab` entry with `user` or `users` and an `X-mount.mode`, `X-mount.owner`, or `X-mount.group` option can use `renameat2(RENAME_EXCHANGE)` to race a writable ancestor of the target and redirect the privileged ownership or mode change to a root-owned path, potentially gaining root privileges. This issue is fixed in 2.41.5 and 2.42.2.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
References	DSA-6442-1
Debian Bugs	1140194

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
util-linux (PTS)	bookworm	2.38.1-5+deb12u3	fixed
	bookworm (security)	2.38.1-5+deb12u1	fixed
	trixie (security), trixie	2.41.5-0+deb13u1	fixed
	forky, sid	2.42.4-1	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Origin	Debian Bugs
util-linux	source	bullseye	(not affected)
util-linux	source	bookworm	(not affected)
util-linux	source	trixie	2.41.5-0+deb13u1	DSA-6442-1
util-linux	source	(unstable)	2.42.2-1		1140194

Notes

[bookworm] - util-linux <not-affected> (Vulnerable code introduced later)
[bullseye] - util-linux <not-affected> (Vulnerable code introduced later)
https://github.com/util-linux/util-linux/security/advisories/GHSA-g8wm-75wr-g2vh
Fixed by: https://github.com/util-linux/util-linux/commit/d0c5adaeb3a3d823aba1377794de8f009b8152cc (v2.42.2)
Fixed by: https://github.com/util-linux/util-linux/commit/897a08c2b11dfa66975c3d24d63c7bf5f5be1a7c (v2.41.5)