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CVE-2026-53612VulnerabilityPublished Updated

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

0

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

CVSS 3.1 base score
7.0High
How severe the flaw is on the 0–10 CVSS scale.
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:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 18 Jun 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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).

Affected software

ProductAffectedFixed in
Ubuntu 26.10util-linuxpkg:deb/ubuntu/util-linux?arch=source&distro=stonkingOther threatsAffected
  • =2.41.3-3ubuntu2
  • =2.42.2-1ubuntu2
Fixed in–
Ubuntu 26.04 LTSutil-linuxpkg:deb/ubuntu/util-linux?arch=source&distro=resoluteOther threatsAffected
  • <2.41.3-3ubuntu2.2
Fixed in
  • 2.41.3-3ubuntu2.2
Ubuntu 25.10util-linuxpkg:deb/ubuntu/util-linux?arch=source&distro=questingOther threatsAffected
  • 2.40.2-14ubuntu1 – 2.41-4ubuntu4.2
6 affected builds
Fixed in–
Ubuntu 24.04 LTSutil-linuxpkg:deb/ubuntu/util-linux?arch=source&distro=nobleOther threatsAffected
  • <2.39.3-9ubuntu6.6
Fixed in
  • 2.39.3-9ubuntu6.6

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.

References

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