All vulnerabilities
CVE-2026-112939GHSA-rfpc-qcw5-3pc4

filelock: SoftFileLock removes a live holder's marker when another user forges the PID in a writable marker

tox-dev filelock
Open in ThreatlineRecord JSON
CVSS
4.7Medium
ExploitationPublic exploit codeCISA's assessment says proof of concept code is public, assessed 20 Oct 2026. Not in the KEV catalogCISA via CVE List
Exploit odds (EPSS)0.14%Chance of exploitation activity in the next 30 days, higher than 3% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed inNone listedNo source names a fixed version. Check the vendor advisory below
Published20 Oct 2026Updated 20 Oct 2026CVE List

What fixes it

No source in this snapshot names a fixed version. The vendor advisories under References are the place to check.

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.

Text from CVE List

Affected versions 1

  • filelockaffected: >= 3.22.0, < 4.2.1CVE List

References 4