What’s Vulnerable › Vulnerabilities

CVE-2026-112906: filelock: SoftFileLock evicts a fresh lock file whose watched age another local user's pre-dated file passed on through inode reuse

• Severity: medium (CVSS 4.7 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-10-20 · updated 2026-10-27
• Weakness: CWE-694

Description

filelock is a platform-independent file lock for Python. From 4.1.0 until 4.2.1, SoftFileLock versions from 4.1.0 can reuse a stale observation when an attacker pre-dates and removes its own marker, at least two lock-user processes are waiting, coarse or matching modification times preserve the observation, and an honest contender creates a fresh marker on the reused inode, causing that live marker to be removed as stale. This issue is fixed in version 4.2.1.

Affected products

• tox-dev filelock: from 4.1.0 before 4.2.1 — fixed in 4.2.1
• tox-dev filelock: from 4.1.0, < 4.2.1

How to fix

Upgrade to a fixed version: tox-dev filelock 4.2.1. Check the vendor advisory for mitigations.

References

• https://github.com/tox-dev/filelock/commit/740ff666b62a88496c8d7394e4e6230605e4d62b
• https://github.com/tox-dev/filelock/releases/tag/4.2.1
• https://github.com/tox-dev/filelock/security/advisories/GHSA-2g95-wg33-c5x2
• https://github.com/tox-dev/filelock/security/advisories/GHSA-2g95-wg33-c5x2

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