util-linux mount hook_owner TOCTOU allows local privilege escalation (util-linux util-linux)
At a glance
- Source
- NVD
- EPSS
- EPSS 0.15 % · percentile 4 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- GitHub_M
- NVD status
- Awaiting Analysis
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.
Weaknesses (CWE)
- CWE-367 — Time-of-check Time-of-use (TOCTOU) Race Condition
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
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | HIGH 7.0 | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H | GitHub_M |
| CVSS 3.1 | HIGH 7.0 | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H | NVD · security-advisories@github.com (Secondary) |
European references
- ENISA EUVD · EUVD-2026-101123
- GCVE · GCVE-0-2026-53612
CERT-FR advisories
- CERTFR-2026-AVI-1385 — Multiples vulnérabilités dans les produits VMware · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1068 — Multiples vulnérabilités dans le noyau Linux de Debian · cert.ssi.gouv.fr
Affected products
| Product | Versions |
|---|---|
| util-linux · util-linux | affected >= 2.39, < 2.41.5 ; affected >= 2.42, < 2.42.2 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |