medium6.3
CVE-2026-112911
filelock: StrictSoftFileLock and SoftReadWriteLock adopt a protocol directory another user created first, losing mutual exclusion
Impact
filelock is a platform-independent file lock for Python. From 3.30.0 until 4.2.1, StrictSoftFileLock versions from 3.30.0 and SoftReadWriteLock versions from 4.0.0 can adopt a protocol directory created first by another local user in a shared parent directory, allowing that user to alter protocol state and admit concurrent holders. This issue is fixed in version 4.2.1.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| pip | filelock | >= 3.30.0, <= 4.2.0 | 4.2.1 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Tox-Dev | Filelock | from 3.30.0 before 4.2.1 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-9c4x-gm8v-wgc4
- https://github.com/tox-dev/filelock/security/advisories/GHSA-9c4x-gm8v-wgc4
- https://nvd.nist.gov/vuln/detail/CVE-2026-112911
- https://github.com/tox-dev/filelock/pull/839
- https://github.com/tox-dev/filelock/commit/bfa066d65a1ba9106f86ee9d027f7588b9c77e03
- https://github.com/tox-dev/filelock/releases/tag/4.2.1