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.

Project Subscriptions

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Advisories
Source ID Title
Debian DSA Debian DSA DSA-6442-1 util-linux security update
Ubuntu USN Ubuntu USN USN-8702-1 util-linux vulnerabilities
Fixes

Solution

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Workaround

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History

Wed, 14 Oct 2026 15:00:00 +0000

Type Values Removed Values Added
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.
Title util-linux mount hook_owner TOCTOU allows local privilege escalation
Weaknesses CWE-367
References
Metrics cvssV3_1

{'score': 7, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-10-14T18:26:36.386Z

Reserved: 2026-06-09T19:39:52.405Z

Link: CVE-2026-53612

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-14T15:17:20.260

Modified: 2026-10-14T15:17:20.260

Link: CVE-2026-53612

cve-icon Redhat

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cve-icon OpenCVE Enrichment

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Weaknesses