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CVE-2026-76642
util-linux libmount Privilege Escalation via Failed Mount Helper
High8.5EPSS 0.22%
- Published
- Updated
- Reserved
- Assigned by
- VulnCheck
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
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| VulnCheckCNA (assigner) | 4.0 | High8.5 | 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 |
| VulnCheckCNA (assigner) | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| NVDNVD · Awaiting Analysis | 4.0 | High8.5 | 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
- EPSS (exploitation in 30 days)
- 0.22% · top 88% of all CVEs (6 Nov 2026)
- CISA SSVC
- Exploitation: poc · Automatable: no · Technical impact: total
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The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.5.
Weakness
Affected products
- affected 2.39 – < 2.41.6
- affected 2.42 – < 2.42.3
References (8)
- GitHub Security Advisory (GHSA-m25x-3hj9-m26f) (opens in a new tab)vendor-advisoryexploit
- Patch Commit (opens in a new tab)patch
- Patch Commit (opens in a new tab)patch
- Patch Commit (opens in a new tab)patch
- https://github.com/util-linux/util-linux/blob/v2.42.2/libmount/src/context_mount.c#L476 (opens in a new tab)technical-description
- https://github.com/util-linux/util-linux/blob/v2.42.2/libmount/src/context_mount.c#L892 (opens in a new tab)technical-description
- https://github.com/util-linux/util-linux (opens in a new tab)product
- VulnCheck Advisory: util-linux libmount Privilege Escalation via Failed Mount Helper (opens in a new tab)third-party-advisory
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-76642)Record last updated .