Time-of-check Time-of-use (TOCTOU) Race Condition in Util-linux - CVE-2026-53613
Published: September 2, 2026
Vulnerability identifier: #VU146717
CSH Severity: Low
CVSS v4: 7.3 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-53613
CWE-ID: CWE-367
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a local user to escalate privileges.
The vulnerability exists due to a time-of-check time-of-use race condition in the mount target path handling in /usr/bin/mount when processing restricted non-root mount requests. A local user can atomically swap an ancestor directory of the mount target path between the permission check and the mount syscall to escalate privileges.
Exploitation requires an /etc/fstab entry with the user or users option where an ancestor directory of the mount target is writable by the attacker.
Affected software
Util-linux
Fedora
util-linux
Fedora
util-linux
How to mitigate CVE-2026-53613
Install security update from vendor's website.
Util-linux - addressed in versions 2.41.5, 2.42.2
util-linux - addressed in versions 2.41.5-1.fc43, 2.41.5-1.fc44
util-linux - addressed in versions 2.41.5-1.fc43, 2.41.5-1.fc44