What’s Vulnerable › Vulnerabilities

CVE-2026-112915: filelock ReadWriteLock: a crafted lock database makes every acquire stall or hang regardless of timeout

• Severity: medium (CVSS 5.5 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 2026-10-21
• Weakness: CWE-400

Description

filelock is a platform-independent file lock for Python. From 3.20.4 until 4.2.1, ReadWriteLock can open a crafted SQLite lock database without bounding schema and query work, allowing another local user who can replace the database to make acquisition stall or hang; versions from 3.20.4 expose this on initial per-instance opening, and versions from 3.30.0 repeat the exposure on every acquisition. This issue is fixed in version 4.2.1.

Affected products

• tox-dev filelock: from 3.20.4 before 4.2.1 — fixed in 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/5e3f2ec0c5fb17cb2635b60b2b68bc63ab81ca2d
• https://github.com/tox-dev/filelock/pull/834
• https://github.com/tox-dev/filelock/releases/tag/4.2.1
• https://github.com/tox-dev/filelock/security/advisories/GHSA-cwqr-hh33-gh44
• https://github.com/tox-dev/filelock/security/advisories/GHSA-cwqr-hh33-gh44

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