SB20260727201 - Race condition in Linux kernel fs



SB20260727201 - Race condition in Linux kernel fs

Published: July 27, 2026

Security Bulletin ID SB20260727201
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) Race condition (CVE-ID: CVE-2026-64378)

CWE-ID: CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

CVSSv4: 6.8 [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]


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

The vulnerability exists due to a race condition in cgroup_writeback_umount() and inode_switch_wbs()/cleanup_offline_cgwb() when unmounting a filesystem while switching inode writeback state. A local user can trigger a container exit or unmount operation during concurrent writeback activity to cause a denial of service.

The issue can lead to busy inodes after unmount and a subsequent use-after-free in writeback cleanup paths.


Remediation

Install update from vendor's website.