CVE-2026-112907
filelock: On Windows an oplock on a soft lock's marker holds SoftFileLock.acquire() past its timeout and blocks the stale break
filelock is a platform-independent file lock for Python. From 3.22.0 until 4.2.1, soft lock classes on Windows read an existing marker with _read_lock_file and remove a stale marker through break_lock_file using pathname operations that wait for an oplock break. Another local account with read access to an unheld marker can keep a Level 1 or batch oplock unanswered, causing SoftFileLock.acquire and related async or fallback locks to wait beyond timeout, blocking=False, and cancel_check. A stale marker under the oplock cannot be broken, but mutual exclusion remains intact and no file other than the marker is accessed. This issue is fixed in version 4.2.1.
Fixes and workarounds
Fix
filelock (PyPI): OSV reports a fixed version 4.2.1. Check the advisory for supported release branches.
Source: OSV GHSA-567q-5qvw-pf92Affected products and versions
| Product | Versions | Authority |
|---|---|---|
| filelock tox-dev |
>= 3.22.0, < 4.2.1 (affected) | CNA: GitHub_M |
filelockfilelock
PyPI |
3.22.0 (affected, PyPI) 3.23.0 (affected, PyPI) 3.24.0 (affected, PyPI) 3.24.1 (affected, PyPI) 3.24.2 (affected, PyPI) 3.24.3 (affected, PyPI) 3.25.0 (affected, PyPI) 3.25.1 (affected, PyPI) 3.25.2 (affected, PyPI) 3.28.0 (affected, PyPI) 3.29.0 (affected, PyPI) 3.29.1 (affected, PyPI) 3.29.2 (affected, PyPI) 3.29.3 (affected, PyPI) 3.29.4 (affected, PyPI) 3.29.5 (affected, PyPI) 3.29.6 (affected, PyPI) 3.29.7 (affected, PyPI) 3.30.0 (affected, PyPI) 3.30.1 (affected, PyPI) 3.30.2 (affected, PyPI) 3.30.3 (affected, PyPI) 3.31.0 (affected, PyPI) 3.31.1 (affected, PyPI) 3.31.2 (affected, PyPI) 3.32.0 (affected, PyPI) 3.32.2 (affected, PyPI) 3.32.3 (affected, PyPI) 3.32.4 (affected, PyPI) 3.32.5 (affected, PyPI) 3.32.6 (affected, PyPI) 3.32.7 (affected, PyPI) 4.0.0 (affected, PyPI) 4.0.1 (affected, PyPI) 4.0.10 (affected, PyPI) 4.0.11 (affected, PyPI) 4.0.12 (affected, PyPI) 4.0.2 (affected, PyPI) 4.0.3 (affected, PyPI) 4.0.4 (affected, PyPI) 4.0.5 (affected, PyPI) 4.0.6 (affected, PyPI) 4.0.7 (affected, PyPI) 4.0.8 (affected, PyPI) 4.0.9 (affected, PyPI) 4.1.0 (affected, PyPI) 4.1.1 (affected, PyPI) 4.1.2 (affected, PyPI) 4.2.0 (affected, PyPI) Ecosystem version events: introduced 3.22.0; fixed 4.2.1 Source events (ECOSYSTEM)Other versions: unaffected |
OSV GHSA-567q-5qvw-pf92 |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 3.1 / 2.5 low |
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L | CNA: GitHub_M |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://github.com/tox-dev/filelock/security/advisories/GHSA-567q-5qvw-pf92CNA: GitHub_M · x_refsource_CONFIRM
- https://github.com/tox-dev/filelock/pull/835CNA: GitHub_M · x_refsource_MISC
- https://github.com/tox-dev/filelock/commit/97d694a9a3ee1721d6c79a480174dfd9b060a080CNA: GitHub_M · x_refsource_MISC
- https://github.com/tox-dev/filelock/commit/e1e825b1992f69fb6b346dc395d5ae4893536c0aCNA: GitHub_M · x_refsource_MISC
- https://github.com/tox-dev/filelock/releases/tag/4.2.1CNA: GitHub_M · x_refsource_MISC
- https://github.com/advisories/GHSA-567q-5qvw-pf92OSV / GitHub Security Advisories · advisory
- https://osv.dev/vulnerability/GHSA-567q-5qvw-pf92OSV / GitHub Security Advisories · osv
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