SB20260918412 - Improper access control in Linux kernel btrfs
Published: September 18, 2026
Security Bulletin ID
SB20260918412
CSH Severity
Low
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Local access
Highest impact
Data manipulation
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 vulnerability.
1) Improper access control (CVE-ID: CVE-2026-90263)
CWE-ID: CWE-284 - Improper Access Control
CVSSv4: 4.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]
The vulnerability allows a local user to modify POSIX ACLs on a read-only Btrfs filesystem.
The vulnerability exists due to improper access control in the btrfs_set_acl POSIX ACL-setting path when setting a POSIX ACL on a Btrfs filesystem whose read-only property is enabled. A local user can set a POSIX ACL to modify POSIX ACLs on a read-only Btrfs filesystem.
Remediation
Install update from vendor's website.