filelock: SoftFileLock stale-break restore follows a swapped-in symbolic link and hard-links a file of the user running the lock into the lock directory

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

When a soft-lock stale break finds that the marker (the lock file at ) it renamed aside was a live one recreated by a successor, the restore branch of break_lock_file() checks the break name with lstat (a check that reads a name without following a symbolic link) and then calls os.link(break_path, lock_file) by name. On CPython 3.12 and later on Linux (and on macOS) that call follows a symbolic link (a file that redirects to another path). A local user (the other user below) who can write a sha…

GitHub Advisory Databaseで読む

2026/10/24 07:00、GitHub Advisory Databaseが「filelock: SoftFileLock stale-break restore follows a swapped-in symbolic link and hard-links a file of the user running the lock into the lock directory」を公開しました (種別: 脆弱性アドバイザリ)。重大度は「警告」(medium) です。関連する技術: Python。CVE: CVE-2026-112914。