What’s Vulnerable › Vulnerabilities

CVE-2026-112936: filelock: ReadWriteLock follows a symlink at the lock path into SQLite

• Severity: medium (CVSS 6.1 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-59

Description

filelock is a platform-independent file lock for Python. From 3.20.4 until 4.0.9, ReadWriteLock and AsyncReadWriteLock versions from 3.20.4 resolve the lock path and pass it to SQLite without rejecting a final symbolic link, allowing another local user who can create names in the lock directory to redirect database creation and locking or split mutual exclusion between targets. This issue is fixed in version 4.0.9.

Affected products

• tox-dev filelock: from 3.20.4 before 4.0.9 — fixed in 4.0.9

How to fix

Upgrade to a fixed version: tox-dev filelock 4.0.9. Check the vendor advisory for mitigations.

References

• https://github.com/tox-dev/filelock/commit/4d45e83caf7e31f9a12fb44526bdc07f70114f04
• https://github.com/tox-dev/filelock/releases/tag/4.0.9
• https://github.com/tox-dev/filelock/security/advisories/GHSA-j8f7-rjxc-mr56
• https://github.com/tox-dev/filelock/security/advisories/GHSA-j8f7-rjxc-mr56

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