SB20260918396 - Deadlock in Linux kernel btrfs
Published: September 18, 2026
Security Bulletin ID
SB20260918396
CSH Severity
Low
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Local access
Highest impact
Denial of service
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 vulnerability.
1) Deadlock (CVE-ID: CVE-2026-90265)
CWE-ID: CWE-833 - Deadlock
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 improper lock ordering in btrfs defragmentation when reserving delayed-allocation space while holding dirty and locked folios and an extent-range lock. A local user can perform filesystem operations that trigger btrfs defragmentation to cause a denial of service.
The deadlock was observed with autodefrag and flushoncommit enabled.
Remediation
Install update from vendor's website.