{"id":"CVE-2026-76642","title":"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","summary":"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…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cwe":["CWE-390"],"published":"2026-09-03","updated":"2026-09-24","sourceUpdated":"2026-09-24T20:28:01.780","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-76642","references":[{"url":"https://github.com/util-linux/util-linux","label":"disclosure@vulncheck.com"},{"url":"https://github.com/util-linux/util-linux/blob/v2.42.2/libmount/src/context_mount.c#L476","label":"disclosure@vulncheck.com"},{"url":"https://github.com/util-linux/util-linux/blob/v2.42.2/libmount/src/context_mount.c#L892","label":"disclosure@vulncheck.com"},{"url":"https://github.com/util-linux/util-linux/commit/1d14676ea70003e9f5b2a6a76af0cadb1190411a","label":"disclosure@vulncheck.com"},{"url":"https://github.com/util-linux/util-linux/commit/a15c00a9e545aa8b9cf6ec0f888ff6c7b3eaeedc","label":"disclosure@vulncheck.com"},{"url":"https://github.com/util-linux/util-linux/commit/f57cea130839c0af8dc0525274267ae4cfd66bbf","label":"disclosure@vulncheck.com"},{"url":"https://github.com/util-linux/util-linux/security/advisories/GHSA-m25x-3hj9-m26f","label":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/util-linux-libmount-privilege-escalation-via-failed-mount-helper","label":"disclosure@vulncheck.com"},{"url":"https://github.com/util-linux/util-linux/security/advisories/GHSA-m25x-3hj9-m26f","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-76642.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-76642"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2521999"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-76642"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-76642"},{"url":"https://access.redhat.com/errata/RHSA-2026:63162"}],"tags":["nvd","csaf","vex","red-hat"],"epss":0.00216,"epssPercentile":0.11902,"ingestedAt":"2026-09-24T20:51:40.240Z","vendor":"Red Hat","product":"Red Hat Enterprise Linux 10","affected":["enterprise_linux 10","hardened_images"],"patched":["hardened_images"],"slug":"CVE-2026-76642","body":"## Overview\n\nutil-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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **RHSA-2026:63162** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-09-03 · [advisory](https://access.redhat.com/errata/RHSA-2026:63162)\n- **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 10 · no fix planned: Red Hat Enterprise Linux 10 · updated 2026-10-01 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-76642.json)","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}