filelock: SoftReadWriteLock follows a lock tree swapped in after its first acquire and writes lock records into directories of the user running the lock

影響: pip:filelock >= 4.1.0, <= 4.2.0 → 4.2.1

SoftReadWriteLock (and AsyncSoftReadWriteLock, which wraps one) checks once per lock object, by name, that .rw, .rw/gen and .rw/holders are real directories and not symbolic links (files that redirect to another path). It then keeps only a boolean. Every later record operation resolves the full path again, and O_NOFOLLOW (a flag that makes an open fail when the final name is a symbolic link) protects the last component only. Another local user (the other user below) who can write the directory…

Read on GitHub Advisory Database

On 10/29/2026, 06:09 AM, GitHub Advisory Database published "filelock: SoftReadWriteLock follows a lock tree swapped in after its first acquire and writes lock records into directories of the user running the lock" (type: Advisory). Severity is "Low" (low). Related technologies: Python. CVE: CVE-2026-112941.