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
Description
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.
INFO
Published Date :
Nov. 5, 2026, 10:17 p.m.
Last Modified :
Nov. 10, 2026, 5:17 a.m.
Remotely Exploit :
No
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | LOW | github | ||||
| CVSS 3.1 | LOW | [email protected] |
Solution
- Update filelock to version 4.2.1 or later.
- Consider directory ACL restrictions for soft lock markers.
- Use default executor for AsyncSoftFileLock.
- Implement robust timeout and cancellation logic.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-112907.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-112907 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-112907
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-112907 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-112907 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Nov. 10, 2026
Action Type Old Value New Value Added Reference https://github.com/tox-dev/filelock/security/advisories/GHSA-567q-5qvw-pf92 Added SSVC {'id': 'CVE-2026-112907', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-11-10T04:38:09.727508Z'} -
New CVE Received by [email protected]
Nov. 05, 2026
Action Type Old Value New Value Added Description 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. Added CVSS V3.1 AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L Added CWE CWE-667 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/112xxx/CVE-2026-112907.json">CVE-2026-112907</a> Added Reference https://github.com/tox-dev/filelock/commit/97d694a9a3ee1721d6c79a480174dfd9b060a080 Added Reference https://github.com/tox-dev/filelock/commit/e1e825b1992f69fb6b346dc395d5ae4893536c0a Added Reference https://github.com/tox-dev/filelock/pull/835 Added Reference https://github.com/tox-dev/filelock/releases/tag/4.2.1 Added Reference https://github.com/tox-dev/filelock/security/advisories/GHSA-567q-5qvw-pf92