CVE-2026-22701: medium-severity vulnerability in tox-dev filelock
filelock Time-of-Check-Time-of-Use (TOCTOU) Symlink Vulnerability in SoftFileLock
Published · Updated
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13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 5.3epss 0.1%
filelock is a platform-independent file lock for Python. Prior to version 3.20.3, a TOCTOU race condition vulnerability exists in the SoftFileLock implementation of the filelock package. An attacker with local filesystem access and permission to create symlinks can exploit a race condition between the permission validation and file creation to cause lock operations to fail or behave unexpectedly. The vulnerability occurs in the _acquire() method between raise_on_not_writable_file() (permission check) and os.open() (file creation). During this race window, an attacker can create a symlink at the lock file path, potentially causing the lock to operate on an unintended target file or leading to denial of service. This issue has been patched in version 3.20.3.
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:H
Affected products
tox-dev · filelockRelated CVEs — tox-dev filelock
In the same product, most dangerous first.
CVE-2026-112934MEDIUMfilelock: SoftReadWriteLock holder refresh writes through a hard link and hangs on a named pipe that another local user renames over its recordEPSS 0.2%CVE-2026-112936MEDIUMfilelock: ReadWriteLock follows a symlink at the lock path into SQLiteEPSS 0.2%CVE-2026-112909MEDIUMfilelock: UnixFileLock truncates and chmods any regular file another user renames or hard-links onto the lock pathEPSS 0.2%CVE-2026-112915MEDIUMfilelock ReadWriteLock: a crafted lock database makes every acquire stall or hang regardless of timeoutEPSS 0.2%CVE-2026-112912LOWfilelock: Symlink swap during SoftFileLock's writability check leaks whether a path exists and is writable by the lock takerEPSS 0.2%CVE-2025-68146MEDIUMfilelock has TOCTOU race condition that allows symlink attacks during lock file creationEPSS 0.2%