filelock is a platform-independent file lock for Python. From 4.0.0 until 4.2.1, SoftReadWriteLock refreshes holder records by name, allowing another local user with rename access to the lock directory to replace a record with a named pipe and stall the lock, or under a permissive hard-link policy to link a reachable target file and cause the lock user to write through it. This issue is fixed in version 4.2.1.
https://github.com/tox-dev/filelock/security/advisories/GHSA-fj95-fr6c-h845
https://github.com/tox-dev/filelock/releases/tag/4.2.1
https://github.com/tox-dev/filelock/pull/842
https://github.com/tox-dev/filelock/commit/bfa066d65a1ba9106f86ee9d027f7588b9c77e03