CVE-2026-52906

Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)

Description In the 9p filesystem implementation, the v9fs apply options() function incorrectly applies parsed mount flags using a bitwise OR operation instead of replacing existing flags. For 9P2000.L, the v9fs session init() function sets V9FS ACCESS CLIENT as the default. When a user mounts with "access=user", both bits are set, causing access mode checks to fail as they require exact value matches. This leads the v9fs fid lookup() function to use INVALID UID (nobody/65534) instead of current fsuid() for all fid lookups, preventing the root user from performing privileged operations such as chown.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.