CVE-2026-112939filelock: SoftFileLock removes a live holder's marker when another user forges the PID in a writable marker
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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filelock is a platform-independent file lock for Python. From 3.22.0 until 4.2.1, SoftFileLock can trust a forged process identifier in a marker that an attacker can modify but cannot remove, allowing an authorized contender such as another process of the holder's account or root to act as a confused deputy, remove the live marker, and admit another holder. 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-345
- 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
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-rfpc-qcw5-3pc4x-refsource-confirm
- https://github.com/tox-dev/filelock/pull/836x-refsource-misc
- https://github.com/tox-dev/filelock/commit/eeceaa846cbe4df72718d94c8371ca1ab8f5b3ccx-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.