CVE-2026-78410
Util-linux: util-linux: restricted bind mounts do not pin the source, allowing x-mount.owner/group/mode redirection
A flaw was found in util-linux. Restricted bind mounts take the source path from fstab but do not pin that source before the privileged mount. A local unprivileged user who can replace the authorized source or a writable ancestor can redirect SUID mount(8) to bind another host directory. If the fstab entry also sets X-mount.owner, X-mount.group, or X-mount.mode, root then changes ownership or mode on that redirected inode.
Fixes and workarounds
Workaround
Upgrade to util-linux v2.41.6, v2.42.3, or later. Until a fix is applied, do not allow unprivileged /etc/fstab bind or rbind entries that also specify X-mount.owner, X-mount.group, or X-mount.mode, especially when the bind source is below a user-writable ancestor.
Source: CNA: redhatAffected products and versions
| Product | Versions | Authority |
|---|---|---|
| Red Hat Enterprise Linux 10 Red Hat util-linux
https://access.redhat.com/downloads/content/package-browser/ |
≥ 0:2.40.2-18.el10_2.20; < * (unaffected, rpm)
Other versions: affected |
CNA: redhat |
| Red Hat Hardened Images Red Hat util-linux-main
https://catalog.redhat.com/software/containers/ |
≥ 2.42.2-3.4.hum1; < * (unaffected, rpm)
Other versions: affected |
CNA: redhat |
| Red Hat Enterprise Linux 7 Red Hat util-linux
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: unaffected |
CNA: redhat |
| Red Hat Enterprise Linux 8 Red Hat util-linux
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: unaffected |
CNA: redhat |
| Red Hat Enterprise Linux 9 Red Hat rhel8/flatpak-runtime
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: unaffected |
CNA: redhat |
| Red Hat Enterprise Linux 9 Red Hat rhel8/flatpak-sdk
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: unaffected |
CNA: redhat |
| Red Hat Enterprise Linux 9 Red Hat util-linux
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: unaffected |
CNA: redhat |
| Red Hat OpenShift Container Platform 4 Red Hat openshift/ose-rhel-coreos-8
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: unaffected |
CNA: redhat |
| Red Hat OpenShift Container Platform 4 Red Hat openshift/ose-rhel-coreos-9
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: unaffected |
CNA: redhat |
| Red Hat OpenShift Container Platform 5 Red Hat openshift/ose-rhel-coreos-9
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: unaffected |
CNA: redhat |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 3.1 / 7.8 high |
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H | CNA: redhat |
Exploit evidence
- https://github.com/util-linux/util-linux/security/advisories/GHSA-rh77-686x-2f2m
exploit · ADP: CISA-ADP
References
- https://access.redhat.com/errata/RHSA-2026:63162CNA: redhat · vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:93461CNA: redhat · vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/security/cve/CVE-2026-78410CNA: redhat · vdb-entry, x_refsource_REDHAT
- https://bugzilla.redhat.com/show_bug.cgi?id=2522684CNA: redhat · issue-tracking, x_refsource_REDHAT
- https://github.com/util-linux/util-linux/security/advisories/GHSA-rh77-686x-2f2mCNA: redhat
- https://github.com/util-linux/util-linux/security/advisories/GHSA-rh77-686x-2f2mADP: CISA-ADP · exploit