CVE-2026-76642
util-linux libmount Privilege Escalation via Failed Mount Helper
- State
- Published
- Severity
- 8.5 High
- Published
- Sep 3, 2026
- Updated
- Sep 3, 2026
- Reserved
- Aug 19, 2026
Description
util-linux versions through 2.41.5 and 2.42.2 fail to check mount helper exit status before running post-mount hooks, allowing unprivileged users to execute privileged operations on pre-existing filesystems. Attackers can exploit X-mount.idmap or X-mount.owner hooks to clone filesystems with inherited suid bits or modify target inode permissions after a helper fails, achieving privilege escalation.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 8.5 High | 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 | VulnCheck |
| 3.1 | 7.8 High | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H | VulnCheck |
Weaknesses
- CWE-390 Detection of Error Condition Without Action
Affected Products
| Product | Versions |
|---|---|
util-linuxutil-linux |
|
References
- GitHub Security Advisory (GHSA-m25x-3hj9-m26f)vendor-advisory
- Patch Commitpatch
- Patch Commitpatch
- Patch Commitpatch
- https://github.com/util-linux/util-linux/blob/v2.42.2/libmount/src/context_mount.c#L476technical-description
- https://github.com/util-linux/util-linux/blob/v2.42.2/libmount/src/context_mount.c#L892technical-description
- https://github.com/util-linux/util-linuxproduct
- VulnCheck Advisory: util-linux libmount Privilege Escalation via Failed Mount Helperthird-party-advisory
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