CVE-2026-53612highCWE-367

CVE-2026-53612: high-severity vulnerability in util-linux

util-linux mount hook_owner TOCTOU allows local privilege escalation

Published

18Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 7
exploitation probability
—
observed exploitation
nono source reports it
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.
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Affected products
util-linux · util-linux
Related CVEs — util-linux

In the same product, most dangerous first.

CVE-2026-76642HIGHutil-linux libmount Privilege Escalation via Failed Mount HelperEPSS 0.2%CVE-2025-14104MEDIUMUtil-linux: util-linux: heap buffer overread in setpwnam() when processing 256-byte usernamesEPSS 0.2%CVE-2026-27456MEDIUMutil-linux: TOCTOU Race Condition in util-linux mount(8) - Loop Device SetupEPSS 0.1%CVE-2026-53615HIGHutil-linux libblkid DOS extended-partition overflow produces invalid partition metadataEPSS —CVE-2026-53614HIGHutil-linux LIBMOUNT_FORCE_MOUNT2 allows nosuid and noexec bypassEPSS —CVE-2026-53613HIGHutil-linux mount target TOCTOU allows local privilege escalationEPSS —
References
https://github.com/util-linux/util-linux/commit/24da33905c7115c4cbccd0afb2a469804e96467ahttps://github.com/util-linux/util-linux/commit/722c96974dd4009a334e4aee556eedaab5fb94b4https://github.com/util-linux/util-linux/commit/897a08c2b11dfa66975c3d24d63c7bf5f5be1a7chttps://github.com/util-linux/util-linux/commit/d0c5adaeb3a3d823aba1377794de8f009b8152cchttps://github.com/util-linux/util-linux/releases/tag/v2.41.5https://github.com/util-linux/util-linux/releases/tag/v2.42.2https://github.com/util-linux/util-linux/security/advisories/GHSA-g8wm-75wr-g2vh