SB2026062653 - Time-of-check Time-of-use (TOCTOU) Race Condition in Linux kernel md driver



SB2026062653 - Time-of-check Time-of-use (TOCTOU) Race Condition in Linux kernel md driver

Published: June 26, 2026

Security Bulletin ID SB2026062653
CSH Severity
Low
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Local access
Highest impact Denial of service

Breakdown by Severity

Low 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Time-of-check Time-of-use (TOCTOU) Race Condition (CVE-ID: CVE-2026-53265)

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

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear


The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to a check-then-act race condition in smq_invalidate_mapping() in the dm-cache-policy-smq component when invalidating cache blocks concurrently. A local user can trigger concurrent invalidation operations to cause a denial of service.

The issue can corrupt the SMQ queues or hash table and may result in a double free condition.


Remediation

Install update from vendor's website.