CVE-2026-22701
Publication date 10 January 2026
Last updated 13 January 2026
Ubuntu priority
Description
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.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| python-filelock | 25.10 questing |
Needs evaluation
|
| 25.04 plucky |
Needs evaluation
|
|
| 24.04 LTS noble |
Needs evaluation
|
|
| 22.04 LTS jammy |
Needs evaluation
|
|
| 20.04 LTS focal |
Needs evaluation
|
|
| 18.04 LTS bionic |
Needs evaluation
|
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score |
5.3 · Medium
|
| Attack vector | Local |
| Attack complexity | High |
| Privileges required | Low |
| User interaction | None |
| Scope | Unchanged |
| Confidentiality | None |
| Integrity impact | Low |
| Availability impact | High |
| Vector | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:H |