File Lock Vulnerability in Python Library Affects Multiple Versions
CVE-2026-112911

6.3MEDIUM

Key Information:

Vendor

Tox-dev

Status
Filelock
Vendor
CVE Published:
20 October 2026

What is CVE-2026-112911?

The filelock library, used for implementing file locks in Python, has a vulnerability that affects versions 3.30.0 to 4.2.1. This flaw allows a local user in a shared directory to hijack the protocol directory created by another user, enabling them to modify the state and allow for concurrent access without proper authorization. This issue has been addressed in version 4.2.1, which mitigates the risk by preventing such protocol adoption. Users are strongly advised to upgrade to the latest version to secure their applications.

Affected Version(s)

filelock >= 3.30.0, < 4.2.1

References

https://github.com/tox-dev/filelock/security/advisories/G...
x_refsource_CONFIRM
https://github.com/tox-dev/filelock/pull/839
x_refsource_MISC
https://github.com/tox-dev/filelock/commit/bfa066d65a1ba9...
x_refsource_MISC

CVSS V3.1

Score:
6.3
Severity:
MEDIUM
Confidentiality:
None
Integrity:
High
Availability:
None
Attack Vector:
Local
Attack Complexity:
High
Privileges Required:
Low
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.