Improper access control in Linux kernel - CVE-2026-52906
Published: June 10, 2026
Vulnerability identifier: #VU134163
CSH Severity: Low
CVSS v4.0: 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/E:U/U:Clear
CVE-ID: CVE-2026-52906
CWE-ID: CWE-284
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vendor: Linux Foundation
Affected software:
Linux kernel
Linux kernel
Detailed vulnerability description
The vulnerability allows a local user to bypass privileged file operations on a mounted 9p filesystem.
The vulnerability exists due to improper access control in v9fs_apply_options() and v9fs_fid_lookup() when processing mount access mode options. A local user can mount the filesystem with the "access=user" option to cause fid lookups to use INVALID_UID instead of current_fsuid().
This issue affects 9P2000.L mounts because conflicting access mode bits can be set at the same time, causing access mode checks to match neither mode.
How to mitigate CVE-2026-52906
Install security update from vendor's repository.