CVE-2026-112908: medium-severity vulnerability in tox-dev filelock
filelock: StrictSoftFileLock creates its claim directories without the lock mode, so another local user with a write bit on them can end a live hold
Published
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
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. From version 3.30.0 until version 4.2.1, StrictSoftFileLock and AsyncStrictSoftFileLock on POSIX systems create coordination and claim directories without applying the caller’s restrictive lock mode. A permissive umask or inherited default ACL can leave these directories writable by another local user, allowing that user to delete an active holder’s claims. Another authorized process can then acquire the lock while the original holder remains in its critical section. An attacker can also plant malformed claims to prevent acquisition. This issue is fixed in version 4.2.1.
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:L
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%
References
https://github.com/tox-dev/filelock/commit/8cf51802158b9cf7e1fc560c2da30491a662cfdehttps://github.com/tox-dev/filelock/commit/bfa066d65a1ba9106f86ee9d027f7588b9c77e03https://github.com/tox-dev/filelock/pull/839https://github.com/tox-dev/filelock/releases/tag/4.2.1https://github.com/tox-dev/filelock/security/advisories/GHSA-6627-m3xw-93mp