--- title: "CVE-2026-112940: filelock - Race Condition" description: "filelock 3.20.4 to 4.2.1 contains a race condition caused by SQLite database and side file reopening by name on POSIX systems, letting attackers with rename access overwrite or unlink files, exploit requires writable adjacent hot journal." url: https://panop.io/threat-heartbeat/CVE-2026-112940/ --- # CVE-2026-112940 filelock - Race Condition filelock 3.20.4 to 4.2.1 contains a race condition caused by SQLite database and side file reopening by name on POSIX systems, letting attackers with rename access overwrite or unlink files, exploit requires writable adjacent hot journal. CVSS base score 7.1 /10 High CISA KEV Not listed Public exploit None known [View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-112940) ## Details Type Race Condition Impact Data Tampering, Denial Of Service CVSS vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H Published 20 October 2026 Updated 21 October 2026 Weakness [CWE-363](https://cwe.mitre.org/data/definitions/363.html) ## Vendor fix Update to version 4.2.1 or later. Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them. ## References - [https://nvd.nist.gov/vuln/detail/CVE-2026-112940](https://nvd.nist.gov/vuln/detail/CVE-2026-112940) - [https://github.com/tox-dev/filelock/commit/5e3f2ec0c5fb17cb2635b60b2b68bc63ab81ca2d](https://github.com/tox-dev/filelock/commit/5e3f2ec0c5fb17cb2635b60b2b68bc63ab81ca2d) - [https://github.com/tox-dev/filelock/pull/834](https://github.com/tox-dev/filelock/pull/834) - [https://github.com/tox-dev/filelock/releases/tag/4.2.1](https://github.com/tox-dev/filelock/releases/tag/4.2.1) - [https://github.com/tox-dev/filelock/security/advisories/GHSA-v4x8-3wr5-3wq8](https://github.com/tox-dev/filelock/security/advisories/GHSA-v4x8-3wr5-3wq8) [← All CVEs](https://panop.io/threat-heartbeat/) ## What this record can't tell you - Whether you run the affected software, and where - Whether an attacker can actually reach and exploit it - The misconfigurations that never get a CVE number - What it would cost the business, ranked into what to fix first Panop answers these inside your environment, for this CVE and every other finding. [Book a demo](https://panop.io/demo)