SB2026090247 - Multiple vulnerabilities in Util-linux

CSH
CYBERSECURITY HELP
Sign In REGISTER

Main Vulnerability Database SB2026090247

SB2026090247 - Multiple vulnerabilities in Util-linux

Published: September 2, 2026

Security Bulletin ID SB2026090247
CSH Severity
Low
Patch available
YES
Number of vulnerabilities 3
Exploitation vector Local access
Highest impact Code execution

Breakdown by Severity

Low 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 3 vulnerabilities.


1) Time-of-check Time-of-use (TOCTOU) Race Condition (CVE-ID: CVE-2026-53612)

CWE-ID: CWE-367 - Time-of-check Time-of-use (TOCTOU) Race Condition

CVSSv4: 7.3 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a local user to escalate privileges.

The vulnerability exists due to a time-of-check time-of-use race condition in the mount(8) hook_owner.c post-mount hook when performing path-based chmod() and lchown() operations on the mount target after mount() completes. A local user can swap a path component with renameat2(RENAME_EXCHANGE) to escalate privileges.

Exploitation requires an /etc/fstab entry with both user and X-mount.mode=, X-mount.owner=, or X-mount.group= options, and the mount target path must have a writable ancestor directory.


2) Time-of-check Time-of-use (TOCTOU) Race Condition (CVE-ID: CVE-2026-53613)

CWE-ID: CWE-367 - Time-of-check Time-of-use (TOCTOU) Race Condition

CVSSv4: 7.3 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a local user to escalate privileges.

The vulnerability exists due to a time-of-check time-of-use race condition in the mount target path handling in /usr/bin/mount when processing restricted non-root mount requests. A local user can atomically swap an ancestor directory of the mount target path between the permission check and the mount syscall to escalate privileges.

Exploitation requires an /etc/fstab entry with the user or users option where an ancestor directory of the mount target is writable by the attacker.


3) Reliance on Untrusted Inputs in a Security Decision (CVE-ID: CVE-2026-53614)

CWE-ID: CWE-807 - Reliance on Untrusted Inputs in a Security Decision

CVSSv4: 7.3 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a local user to escalate privileges.

The vulnerability exists due to reliance on untrusted environment variables in libmount mount path selection when processing the LIBMOUNT_FORCE_MOUNT2 environment variable in the SUID mount(8) binary. A local user can set LIBMOUNT_FORCE_MOUNT2=always and trigger concurrent mount operations to escalate privileges.

Exploitation requires an /etc/fstab bind entry with user, nosuid, and noexec options where the bind source contains a SUID root binary.


Remediation

Install update from vendor's website.

References