{"id":"CVE-2026-112911","title":"filelock: StrictSoftFileLock and SoftReadWriteLock adopt a protocol directory another user created first, losing mutual exclusion","summary":"filelock is a platform-independent file lock for Python. From 3.30.0 until 4.2.1, StrictSoftFileLock versions from 3.30.0 and SoftReadWriteLock versions from 4.0.0 can adopt a protocol directory created first by another local user in a s…","severity":"medium","cvss":6.3,"cvssVector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:H","cvssSource":"cna","cwe":["CWE-283"],"vendor":"tox-dev","product":"filelock","affected":["filelock >= 3.30.0, < 4.2.1"],"published":"2026-10-20","updated":"2026-10-20","sourceUpdated":"2026-10-20T14:21:24.480Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-112911","references":[{"url":"https://github.com/tox-dev/filelock/security/advisories/GHSA-9c4x-gm8v-wgc4","label":"https://github.com/tox-dev/filelock/security/advisories/GHSA-9c4x-gm8v-wgc4"},{"url":"https://github.com/tox-dev/filelock/pull/839","label":"https://github.com/tox-dev/filelock/pull/839"},{"url":"https://github.com/tox-dev/filelock/commit/bfa066d65a1ba9106f86ee9d027f7588b9c77e03","label":"https://github.com/tox-dev/filelock/commit/bfa066d65a1ba9106f86ee9d027f7588b9c77e03"},{"url":"https://github.com/tox-dev/filelock/releases/tag/4.2.1","label":"https://github.com/tox-dev/filelock/releases/tag/4.2.1"}],"tags":["cve.org"],"ingestedAt":"2026-10-20T15:09:24.127Z","slug":"CVE-2026-112911","body":"## Overview\n\nfilelock is a platform-independent file lock for Python. From 3.30.0 until 4.2.1, StrictSoftFileLock versions from 3.30.0 and SoftReadWriteLock versions from 4.0.0 can adopt a protocol directory created first by another local user in a shared parent directory, allowing that user to alter protocol state and admit concurrent holders. This issue is fixed in version 4.2.1.\n\n## Affected\n\n- `filelock >= 3.30.0, < 4.2.1`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":35,"depthScoreParts":{"impact":34.7,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}