CVE-2026-76642CWE-390

CVE-2026-76642

High · published September 3, 2026

CVSS v3.1
7.8
EPSS
0%
Percentile
7.2
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
7.8 · HIGH
Vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS v4.0
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
EPSS
0.00176 · 7.2th percentile
Weakness
CWE-390 · Detection of Error Condition Without Action
Published
2026-09-03T17:06Z
References (9)
https://github.com/util-linux/util-linux · [email protected]https://github.com/util-linux/util-linux/blob/v2.42.2/libmount/src/context_mount.c#L476 · [email protected]https://github.com/util-linux/util-linux/blob/v2.42.2/libmount/src/context_mount.c#L892 · [email protected]https://github.com/util-linux/util-linux/commit/1d14676ea70003e9f5b2a6a76af0cadb1190411a · [email protected]https://github.com/util-linux/util-linux/commit/a15c00a9e545aa8b9cf6ec0f888ff6c7b3eaeedc · [email protected]https://github.com/util-linux/util-linux/commit/f57cea130839c0af8dc0525274267ae4cfd66bbf · [email protected]https://github.com/util-linux/util-linux/security/advisories/GHSA-m25x-3hj9-m26f · [email protected]https://www.vulncheck.com/advisories/util-linux-libmount-privilege-escalation-via-failed-mount-helper · [email protected]https://github.com/util-linux/util-linux/security/advisories/GHSA-m25x-3hj9-m26f · 134c704f-9b21-4f2e-91b3-4a467353bcc0
EPSS history
Timeline
  • 04 SEP 03:45Z
    EPSS moved — → 0%
    epss
  • 03 SEP 10:54Z
    util-linux libmount Privilege Escalation via Failed Mount Helper
    cvelistv5