USN-8702-1: util-linux vulnerabilities

Publication date

31 August 2026

Overview

Several security issues were fixed in util-linux.


Packages

Details

It was discovered that libblkid in util-linux had a heap use-after-free
vulnerability during nested partition probing. An attacker who could
present a crafted block device image could possibly use this issue to
obtain sensitive information or cause a denial of service. (CVE-2026-13595)

It was discovered that the mount utility in util-linux had a time-of-check-
time-of-use vulnerability when setting up loop devices. A local attacker
could possibly use this issue to obtain unauthorized read access to root-
protected files and block devices. (CVE-2026-27456)

It was discovered that the login utility in util-linux improperly
canonicalized hostnames when invoked with the -h option. A remote attacker
could possibly use this issue to bypass host-based access control rules.
This issue only affected Ubuntu 26.04 LTS. (

It was discovered that libblkid in util-linux had a heap use-after-free
vulnerability during nested partition probing. An attacker who could
present a crafted block device image could possibly use this issue to
obtain sensitive information or cause a denial of service. (CVE-2026-13595)

It was discovered that the mount utility in util-linux had a time-of-check-
time-of-use vulnerability when setting up loop devices. A local attacker
could possibly use this issue to obtain unauthorized read access to root-
protected files and block devices. (CVE-2026-27456)

It was discovered that the login utility in util-linux improperly
canonicalized hostnames when invoked with the -h option. A remote attacker
could possibly use this issue to bypass host-based access control rules.
This issue only affected Ubuntu 26.04 LTS. (CVE-2026-3184)

It was discovered that libmount in util-linux had a time-of-check-time-of-
use vulnerability in its ownership hook. A local attacker could possibly
use this issue to gain elevated privileges. This issue only affected Ubuntu
24.04 LTS and Ubuntu 26.04 LTS. (CVE-2026-53612)

It was discovered that libmount in util-linux had a time-of-check-time-of-
use vulnerability that allowed target path redirection during mount
operations. A local attacker could possibly use this issue to gain elevated
privileges. (CVE-2026-53613)

It was discovered that libmount in util-linux improperly handled the
LIBMOUNT_FORCE_MOUNT2 environment variable in the SUID mount utility. A
local attacker could possibly use this issue to bypass nosuid and noexec
mount options and gain elevated privileges. This issue only affected Ubuntu
24.04 LTS and Ubuntu 26.04 LTS. (CVE-2026-53614)

It was discovered that libblkid in util-linux had an integer overflow
vulnerability when parsing DOS partition tables. An attacker who could
present a crafted block device image could possibly use this issue to cause
a denial of service. (CVE-2026-53615)


Update instructions

In general, a standard system update will make all the necessary changes.

Learn more about how to get the fixes.

The problem can be corrected by updating your system to the following package versions:

Ubuntu Release Package Version
26.04 LTS resolute util-linux –  2.41.3-3ubuntu2.2
24.04 LTS noble util-linux –  2.39.3-9ubuntu6.6
22.04 LTS jammy util-linux –  2.37.2-4ubuntu3.6

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