filelock is a platform-independent file lock for Python. From 3.22.0 until 4.2.1, SoftFileLock can break a stale marker after an attacker frees its own marker following the stale read, an honest contender creates a live successor on the reused inode, and the successor's modification time is not newer than the saved observation, causing the live marker to be removed and two holders to be admitted. This issue is fixed in version 4.2.1.
Fix
Patch, vendor advisory and mitigation references on NVD 4
- https://github.com/tox-dev/filelock/commit/740ff666b62a88496c8d7394e4e6230605e4d62b Patch
- https://github.com/tox-dev/filelock/pull/843 Patch
- https://github.com/tox-dev/filelock/security/advisories/GHSA-fq56-3cx3-fjxp Exploit, Mitigation, Patch, Vendor Advisory
- https://github.com/tox-dev/filelock/security/advisories/GHSA-fq56-3cx3-fjxp Exploit, Mitigation, Patch, Vendor Advisory
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 7
- StatusAnalyzed → ModifiedNVD modified 2026-10-28 15:17
- Cpes+1 CPE criteria (now 1)NVD modified 2026-10-21 21:12
- StatusPublished → AnalyzedNVD modified 2026-10-21 21:12
- StatusUndergoing Analysis → PublishedNVD modified 2026-10-20 14:32
- StatusPublished → Undergoing AnalysisNVD modified 2026-10-20 19:50
- StatusReceived → PublishedNVD modified 2026-10-20 14:32
- First seenCVSS 4.7NVD modified 2026-10-20 15:17
Affected (CPE criteria) 1
cpe:2.3:a:tox-dev:filelock:*:*:*:*:*:python:*:*
References 5
- https://github.com/tox-dev/filelock/commit/740ff666b62a88496c8d7394e4e6230605e4d62b Patch
- https://github.com/tox-dev/filelock/pull/843 Patch
- https://github.com/tox-dev/filelock/releases/tag/4.2.1 Release Notes
- https://github.com/tox-dev/filelock/security/advisories/GHSA-fq56-3cx3-fjxp Exploit, Mitigation, Patch, Vendor Advisory
- https://github.com/tox-dev/filelock/security/advisories/GHSA-fq56-3cx3-fjxp Exploit, Mitigation, Patch, Vendor Advisory