filelock: Symlink swap during SoftFileLock's writability check leaks whether a path exists and is writable by the lock taker

影響: pip:filelock >= 3.32.6, <= 4.2.0 → 4.2.1

raise_on_not_writable_file() is the check that SoftFileLock and the locks sharing its acquire path run before every attempt. It looks at the lock path with os.lstat, so that it judges a planted symlink (a file that points at another path) by itself. When the node has no owner-write bit, it then calls os.access(filename, os.W_OK), which follows symlinks. A local user who can create entries in the lock's directory can swap the path between a mode-0466 file and a symlink to a path of their choosin…

在 GitHub Advisory Database 阅读

2026/10/29 06:08，GitHub Advisory Database 发布了“filelock: Symlink swap during SoftFileLock's writability check leaks whether a path exists and is writable by the lock taker”（类型：漏洞公告）。严重程度为“低危”（low）。相关技术：Python。CVE：CVE-2026-112912。