Threats tagged 'brew-bbot-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) leak. The vulnerability affects filelock versions 3.32.6 through 4.2.0 and is mitigated by Linux kernel's fs.protected_symlinks setting in common sticky world-writable directories like /tmp. The impact is limited to leaking existence and writability of a path, with no integrity or availability effects. The vulnerability requires local access, high attack complexity, and observation of the lock user's acquire outcome.