{"id":"CVE-2026-76642","summary":"util-linux libmount Privilege Escalation via Failed Mount Helper","details":"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.","aliases":["GHSA-m25x-3hj9-m26f"],"modified":"2026-09-04T03:47:25.965878737Z","published":"2026-09-03T10:54:08.150Z","database_specific":{"cna_assigner":"VulnCheck","cwe_ids":["CWE-390"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/76xxx/CVE-2026-76642.json","unresolved_ranges":[{"extracted_events":[{"introduced":"2.39"},{"fixed":"2.41.6"},{"introduced":"2.42"},{"fixed":"2.42.3"}],"source":"AFFECTED_FIELD"},{"extracted_events":[{"introduced":"2.39"},{"fixed":"2.41.6"},{"introduced":"2.42"},{"fixed":"2.42.3"}],"source":"CPE_FIELD"}]},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/76xxx/CVE-2026-76642.json"},{"type":"PACKAGE","url":"https://github.com/util-linux/util-linux"},{"type":"ARTICLE","url":"https://github.com/util-linux/util-linux/blob/v2.42.2/libmount/src/context_mount.c#L476"},{"type":"ARTICLE","url":"https://github.com/util-linux/util-linux/blob/v2.42.2/libmount/src/context_mount.c#L892"},{"type":"FIX","url":"https://github.com/util-linux/util-linux/commit/1d14676ea70003e9f5b2a6a76af0cadb1190411a"},{"type":"FIX","url":"https://github.com/util-linux/util-linux/commit/a15c00a9e545aa8b9cf6ec0f888ff6c7b3eaeedc"},{"type":"FIX","url":"https://github.com/util-linux/util-linux/commit/f57cea130839c0af8dc0525274267ae4cfd66bbf"},{"type":"ADVISORY","url":"https://github.com/util-linux/util-linux/security/advisories/GHSA-m25x-3hj9-m26f"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-76642"},{"type":"ADVISORY","url":"https://www.vulncheck.com/advisories/util-linux-libmount-privilege-escalation-via-failed-mount-helper"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/util-linux/util-linux","events":[{"introduced":"0"},{"fixed":"230de59ffbee328506d92d3534e66d56de1afe5d"}],"database_specific":{"extracted_events":[{"introduced":"0"},{"fixed":"2.41.5"}],"source":"DESCRIPTION"}}],"versions":["v2.41.4","v2.41.3","v2.41.2","v2.41.2-rc1","v2.41.1","v2.41","v2.41-rc2","v2.41-rc1","v2.42-start","v2.41-start","v2.41-devel","v2.40-rc1","v2.39","v2.39-rc3","v2.39-rc2","v2.39-rc1","v2.38","v2.38-rc4","v2.38-rc3","v2.38-rc2","v2.38-rc1","v2.37","v2.37-rc2","v2.37-rc1","v2.36","v2.36-rc2","v2.36-rc1","v2.35","v2.35-rc2","v2.35-rc1","v2.34","v2.34-rc2","v2.34-rc1","v2.33","v2.33-rc2","v2.33-rc1","v2.32","v2.32-rc2","v2.32-rc1","v2.31","v2.31-rc2","v2.31-rc1","v2.30","v2.30-rc2","v2.30-rc1","v2.29","v2.29-rc2","v2.29-rc1","v2.28","v2.28-rc2","v2.28-rc1","v2.27","v2.27-rc2","v2.27-rc1","v2.26","v2.26-rc2","v2.26-rc1","v2.25","v2.25-rc2","v2.25-rc1","v2.24","v2.24-rc2","v2.24-rc1","v2.23","v2.23-rc2","v2.23-rc1","v2.22","v2.22-rc2","v2.22-rc1","v2.21","v2.21-rc2","v2.21-rc1","v2.20","v2.20-rc2","v2.20-rc1","v2.19","v2.19-rc3","v2.19-rc2","v2.19-rc1","v2.18","v2.18-rc2","v2.18-rc1","v2.17","v2.17-rc3","v2.17-rc2","v2.17-rc1","v2.16","v2.16-rc2","v2.16-rc1","v2.15","v2.15-rc2","v2.15-rc1","v2.14","v2.14-rc3","v2.14-rc2","v2.14-rc1","v2.13","v2.13-rc3","v2.13-rc2","v2.13-rc1","v2.13-pre7","v2.13-pre6","v2.13-pre5","v2.13-pre4","v2.13-pre3","v2.13-pre2","v2.13-pre1","v2.12r","v2.12r-pre1","v2.12q","v2.12q-pre2","v2.12q-pre1","v2.12p","v2.12o","v2.12m","v2.12l","v2.12k","v2.12j","v2.12i","v2.12h","v2.12d","v2.12b","v2.12a","v2.12pre","v2.12","v2.11y","v2.11x","v2.11w","v2.11v","v2.11u","v2.11t","v2.11r","v2.11q","v2.11o","v2.11n","v2.11m","v2.11f","v2.11b","v2.10s","v2.10m","v2.10f","v2.9v","v2.9i","v2.8","v2.7.1","v2.5","v2.2"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-76642.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"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"}]}