Medium 4.7Published Oct 20, 2026

CVE-2026-112935filelock: SoftFileLock stale-lock break removes a live lock file on a reused inode number and admits two holders

Updated under an hour ago (2026-10-21 08:23 UTC)

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It affects tox-dev filelock. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for tox-dev filelock

Exploited in the last 30 days

filelock is a platform-independent file lock for Python. From 3.22.0 until 4.2.1, SoftFileLock can break a stale marker after an attacker frees its own marker following the stale read, an honest contender creates a live successor on the reused inode, and the successor's modification time is not newer than the saved observation, causing the live marker to be removed and two holders to be admitted. This issue is fixed in version 4.2.1.

CVSS: 4.7 MEDIUM (v3.1, CNA)CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N
Weakness (CWE): CWE-367
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Undergoing Analysis
Record last updated: Oct 20, 2026
First seen by InfoSec Signals: Oct 20, 2026

Affected products

Affected products

tox-dev filelock tox_dev:filelock (from the name)	from 3.22.0, < 4.2.1	CNA record

References

https://github.com/tox-dev/filelock/security/advisories/GHSA-fq56-3cx3-fjxpx-refsource-confirm
https://github.com/tox-dev/filelock/pull/843x-refsource-misc
https://github.com/tox-dev/filelock/commit/740ff666b62a88496c8d7394e4e6230605e4d62bx-refsource-misc
https://github.com/tox-dev/filelock/releases/tag/4.2.1x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.