Detection of Error Condition Without Action in Util-linux - CVE-2026-76642
Published: September 2, 2026
Vulnerability identifier: #VU146721
CSH Severity: Low
CVSS v4: 8.5 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-76642
CWE-ID: CWE-390
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 incorrect status handling in libmount post-mount hooks when processing a failed external mount helper. A local user can trigger a nonzero helper exit for a root-controlled fstab entry with X-mount.idmap to escalate privileges.
Exploitation requires SUID-root mount(8), a usable root-controlled fstab entry, a failed external mount helper, and an idmap-capable filesystem target.
Affected software
Util-linux
How to mitigate CVE-2026-76642
Install security update from vendor's website.
Util-linux - addressed in versions 2.41.6, 2.42.3