Time-of-check Time-of-use (TOCTOU) Affecting util-linux package, versions <2.41.3-3ubuntu2.2


Severity

Recommended
medium

Based on Ubuntu security rating.

Threat Intelligence

EPSS
0.12% (2nd percentile)

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  • Snyk IDSNYK-UBUNTU2604-UTILLINUX-17368965
  • published1 Sept 2026
  • disclosed14 Oct 2026

Introduced: 1 Sep 2026

CVE-2026-53612  (opens in a new tab)
CWE-367  (opens in a new tab)

How to fix?

Upgrade Ubuntu:26.04 util-linux to version 2.41.3-3ubuntu2.2 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream util-linux package and not the util-linux package as distributed by Ubuntu. See How to fix? for Ubuntu:26.04 relevant fixed versions and status.

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 Base Scores

version 3.1