Vulnerability · Published Oct 20, 2026 · Assigned by GitHub_M
CVE-2026-112937filelock: ReadWriteLock on the hard-link route deletes any directory another user renames onto its .filelock-* link directory name
Medium 6.1
In plain English
A medium-severity security flaw in filelock from tox-dev. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 5% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
filelock is a platform-independent file lock for Python. From 4.1.0 until 4.2.1, ReadWriteLock can remove a randomized .filelock-* private-hard-link directory during cleanup, allowing another local user with rename access in a non-sticky parent to observe a live name or forge a dead-owner sweep name and rename a sibling directory onto it for deletion. This issue is fixed in version 4.2.1.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | python-filelock | no fix listed | DEBIAN-CVE-2026-112937 |
| Debian:13 | python-filelock | no fix listed | DEBIAN-CVE-2026-112937 |
| Debian:14 | python-filelock | no fix listed | DEBIAN-CVE-2026-112937 |
| PyPI | filelock | 4.2.1 | GHSA-jqc4-5cvw-7w85 |
| Ubuntu:26.04:LTS | python-filelock | no fix listed | UBUNTU-CVE-2026-112937 |
| Ubuntu:26.10 | python-filelock | no fix listed | UBUNTU-CVE-2026-112937 |
Affected products (as reported)
Weakness: CWE-367 · Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:L
References
- https://github.com/tox-dev/filelock/security/advisories/GHSA-jqc4-5cvw-7w85 x_refsource_CONFIRM
- https://github.com/tox-dev/filelock/pull/834 x_refsource_MISC
- https://github.com/tox-dev/filelock/commit/5e3f2ec0c5fb17cb2635b60b2b68bc63ab81ca2d x_refsource_MISC
- https://github.com/tox-dev/filelock/releases/tag/4.2.1 x_refsource_MISC