In util-linux 2.39 through 2.41.4 and 2.42 through 2.42.1, the SUID mount utility's hook_owner.c post-mount hook
Affects util-linuxSource GCVE Database
Not known to be exploited · CVSS 7.0 High · fixed in 2.39.3-9ubuntu6.6 : patch util-linux soon.
Data as of 28 Oct 2026, 22:28 UTC
- Patch
- Available – fixed in 2.39.3-9ubuntu6.6, 2.41.3-3ubuntu2.2
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 18 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade the Ubuntu util-linux to 2.39.3-9ubuntu6.6 (package) or 2.41.3-3ubuntu2.2 (package).
Patches and advisories
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10util-linuxpkg:deb/ubuntu/util-linux?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSutil-linuxpkg:deb/ubuntu/util-linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 25.10util-linuxpkg:deb/ubuntu/util-linux?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSutil-linuxpkg:deb/ubuntu/util-linux?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
util-linux is a random collection of Linux utilities. In util-linux 2.39 through 2.41.4 and 2.42 through 2.42.1, the SUID `mount` utility's `hook_owner.c` post-mount hook performs path-based `chmod()` and `lchown()` operations on a previously validated mount target. A local low-privileged user authorized by an `/etc/fstab` entry with `user` or `users` and an `X-mount.mode`, `X-mount.owner`, or `X-mount.group` option can use `renameat2(RENAME_EXCHANGE)` to race a writable ancestor of the target and redirect the privileged ownership or mode change to a root-owned path, potentially gaining root privileges. This issue is fixed in 2.41.5 and 2.42.2.