CVE-2026-22701

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.
Configurations

No configuration.

History

10 Jan 2026, 06:15

Type Values Removed Values Added
New CVE

Information

Published : 2026-01-10 06:15

Updated : 2026-01-13 14:03


NVD link : CVE-2026-22701

Mitre link : CVE-2026-22701

CVE.ORG link : CVE-2026-22701


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Products Affected

No product.

CWE
CWE-59

Improper Link Resolution Before File Access ('Link Following')

CWE-362

Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

CWE-367

Time-of-check Time-of-use (TOCTOU) Race Condition