Vulnerability in Tox-Dev Filelock

CVE-2026-112907

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.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 2.5 (Low). Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L.

EPSS exploit prediction

EPSS: 0.001 (1.0th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 1st percentile — 1.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

The 30-day trend appears once there are two daily scores.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-112907?
CVE-2026-112907 is a low-severity vulnerability in Tox-Dev Filelock, classified under Improper Locking. CVSS score: 2.5/10. Published 2026-11-05.
How severe is CVE-2026-112907?
Low severity. CVSS v3 base score is 2.5 out of 10.