medium6.1
CVE-2026-112909
filelock: UnixFileLock truncates and chmods any regular file another user renames or hard-links onto the lock path
Impact
filelock is a platform-independent file lock for Python. Prior to 4.2.1, UnixFileLock can truncate a regular file renamed onto the lock path when another local user has actual rename permission, or hard-linked there under a permissive hard-link policy; when an explicit mode is requested, affected versions from 3.10.2 can also change that file's mode. This issue is fixed in version 4.2.1.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| pip | filelock | <= 4.2.0 | 4.2.1 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Tox-Dev | Filelock | before 4.2.1 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-69hj-f68j-2879
- https://github.com/tox-dev/filelock/security/advisories/GHSA-69hj-f68j-2879
- https://nvd.nist.gov/vuln/detail/CVE-2026-112909
- https://github.com/tox-dev/filelock/pull/835
- https://github.com/tox-dev/filelock/commit/e1e825b1992f69fb6b346dc395d5ae4893536c0a
- https://github.com/tox-dev/filelock/releases/tag/4.2.1