Medium 6.3Published Oct 20, 2026

CVE-2026-112911filelock: StrictSoftFileLock and SoftReadWriteLock adopt a protocol directory another user created first, losing mutual exclusion

Updated under an hour ago (2026-10-21 08:20 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 3.30.0 until 4.2.1, StrictSoftFileLock versions from 3.30.0 and SoftReadWriteLock versions from 4.0.0 can adopt a protocol directory created first by another local user in a shared parent directory, allowing that user to alter protocol state and admit concurrent holders. This issue is fixed in version 4.2.1.

CVSS: 6.3 MEDIUM (v3.1, CNA)CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:H
Weakness (CWE): CWE-283
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 3.30.0, < 4.2.1	CNA record

References

https://github.com/tox-dev/filelock/security/advisories/GHSA-9c4x-gm8v-wgc4x-refsource-confirm
https://github.com/tox-dev/filelock/pull/839x-refsource-misc
https://github.com/tox-dev/filelock/commit/bfa066d65a1ba9106f86ee9d027f7588b9c77e03x-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.