Improper access control in Linux kernel - CVE-2026-90263
Published: September 18, 2026
Vulnerability identifier: #VU151225
CSH Severity: Low
CVSS v4: 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]
CVE-ID: CVE-2026-90263
CWE-ID: CWE-284
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
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.
Affected software
Linux kernel
How to mitigate CVE-2026-90263
Install security update from vendor's repository.