filelock: On Windows an oplock on a soft lock's marker holds SoftFileLock.acquire() past its timeout and blocks the stale break

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-112907
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-11-05 22:17:46 UTC
Updated2026-11-06 21:40:43 UTC
Descriptionfilelock 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.

Risk And Classification

Primary CVSS: v3.1 2.5 LOW from [email protected]

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L

EPSS: 0.001040000 probability, percentile 0.010300000 (date 2026-11-07)

Problem Types: CWE-667 | CWE-667 CWE-667: Improper Locking

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary2.5LOWCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L
3.1CNADECLARED2.5LOWCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
High
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
Low

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Tox-dev Filelock affected >= 3.22.0, < 4.2.1 Not specified

References

ReferenceSourceLinkTags
github.com/tox-dev/filelock/security/advisories/GHSA-567q-5qvw-pf92 [email protected] github.com
github.com/tox-dev/filelock/releases/tag/4.2.1 [email protected] github.com
github.com/tox-dev/filelock/commit/e1e825b1992f69fb6b346dc395d5ae4893536c0a [email protected] github.com
github.com/tox-dev/filelock/commit/97d694a9a3ee1721d6c79a480174dfd9b060a080 [email protected] github.com
github.com/tox-dev/filelock/pull/835 [email protected] github.com
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