CVE-2026-112939
Medium
Description
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.
SeverityMedium
CVSS4.7
Exploit probability—
ProductTox-dev Filelock
PublishedOct 20, 2026
First seenOct 20, 2026
Weakness typeCWE-345CWE-345
How to fix
Update
- tox-dev filelock4.2.1 or later
- filelock4.2.1 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| tox-dev filelock | 3.22.0 ≤ v < 4.2.1 | 4.2.1 |
| filelockPyPI | 3.22.0 ≤ v ≤ 4.2.0 | 4.2.1 |
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