High severity · published Sep 3, 2026
CVE-2026-76642
util-linux libmount Privilege Escalation via Failed Mount Helper
7.8
CVSS
0.2%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 12% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
UT
util-linux · util-linux
2.39 before 2.41.6; 2.42 before 2.42.3 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-76642
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-76642
github.com
https://github.com/util-linux/util-linux
github.com
https://github.com/util-linux/util-linux/blob/v2.42.2/libmount/src/context_mount.c#L476
github.com
https://github.com/util-linux/util-linux/blob/v2.42.2/libmount/src/context_mount.c#L892
github.com
https://github.com/util-linux/util-linux/commit/1d14676ea70003e9f5b2a6a76af0cadb1190411a
github.com
https://github.com/util-linux/util-linux/commit/a15c00a9e545aa8b9cf6ec0f888ff6c7b3eaeedc
github.com
https://github.com/util-linux/util-linux/commit/f57cea130839c0af8dc0525274267ae4cfd66bbf
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