CVE-2026-53612
util-linux mount hook_owner TOCTOU allows local privilege escalation
- State
- Published
- Severity
- 7.0 High
- Published
- Oct 14, 2026
- Updated
- Oct 14, 2026
- Reserved
- Jun 9, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 7.0 High | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H | GitHub_M |
Weaknesses
- CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition
Affected Products
| Product | Versions |
|---|---|
util-linuxutil-linux |
|
References
- https://github.com/util-linux/util-linux/security/advisories/GHSA-g8wm-75wr-g2vh
- https://github.com/util-linux/util-linux/commit/24da33905c7115c4cbccd0afb2a469804e96467a
- https://github.com/util-linux/util-linux/commit/722c96974dd4009a334e4aee556eedaab5fb94b4
- https://github.com/util-linux/util-linux/commit/897a08c2b11dfa66975c3d24d63c7bf5f5be1a7c
- https://github.com/util-linux/util-linux/commit/d0c5adaeb3a3d823aba1377794de8f009b8152cc
- https://github.com/util-linux/util-linux/releases/tag/v2.41.5
- https://github.com/util-linux/util-linux/releases/tag/v2.42.2
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