Threats tagged 'brew-lexicon-cve-2026-112912'

A symlink swap vulnerability in filelock's SoftFileLock writability check allows a local user to leak one bit of information about whether a path exists and is writable by the lock user. This occurs because the check uses os.lstat followed by os.access, which follows symlinks, enabling a time-of-check to time-of-use (TOCTOU) race condition. The vulnerability affects filelock versions 3.32.6 through 4.2.0 and is mitigated on Linux by the fs.protected_symlinks kernel setting in sticky world-writable directories like /tmp. The impact is limited to leaking a single bit of information per lock acquire attempt, with no integrity or availability impact. The vulnerability requires local access, the ability to create entries in the lock directory, and a race condition timing that is complex to achieve.