Time-of-check Time-of-use (TOCTOU) Race Condition in filelock - CVE-2026-22701
Published: January 13, 2026
Vulnerability identifier: #VU121189
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-22701
CWE-ID: CWE-367
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vendor: benediktschmitt (Benedikt Schmitt)
Affected software:
filelock
filelock
Detailed vulnerability description
The vulnerability allows a local user to perform a denial of service attack.
The vulnerability exists due to a race condition in the SoftFileLock implementation of the filelock package. A local user can create a symbolic link to a critical file on the system between the permission validation and file creation to cause lock operations to fail or behave unexpectedly.
How to mitigate CVE-2026-22701
Install updates from vendor's website.