CVE-2026-22701

5.3 MEDIUM 0.1% exploit odds Fix listed Other Library

What it is

filelock is a platform-independent file lock for Python. Prior to version 3.20.3, a TOCTOU race condition vulnerability exists in the SoftFileLock implementation of the filelock package. An attacker with local filesystem access and permission to create symlinks can exploit a race condition between the permission validation and file creation to cause lock operations to fail or behave unexpectedly. The vulnerability occurs in the _acquire() method between raise_on_not_writable_file() (permission check) and os.open() (file creation). During this race window, an attacker can create a symlink at the lock file path, potentially causing the lock to operate on an unintended target file or leading to denial of service. This issue has been patched in version 3.20.3.

At a glance

Exploitability: Can be exploited locally on the machine with a low-privilege account. High risk of service disruption.
Exploit odds: 0.1% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-01-10 06:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-06-17 10:20 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.1% in the next 30 days (EPSS).
Severity: 5.3 MEDIUM (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-01-10 06:15 UTC
Last modified: 2026-06-17 10:20 UTC
Exploit probability: 0.1% · EPSS, next 30 days
Weakness: CWE-59
Record status: Analyzed

Affected

tox-dev Filelock < 3.20.3

Attack profile CVSS 3.1 · 5.3

Attack vector: Local
Complexity: High
Privileges needed: Low
User interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: Low
Availability: High

Raw vector

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:H

Is it in your code?

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Fix and advisories

References

NVD record · CVE.org record