Medium severity · published Oct 20, 2026
CVE-2026-112937
filelock: ReadWriteLock on the hard-link route deletes any directory another user renames onto its .filelock-* link directory name
6.1
CVSS
0.2%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:L
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
None
Integrity
High
Availability
Low
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 5% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
FI
filelock · tox-dev
>= 4.1.0, < 4.2.1 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-112937
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-112937
Patch
https://github.com/tox-dev/filelock/commit/5e3f2ec0c5fb17cb2635b60b2b68bc63ab81ca2d
Patch
https://github.com/tox-dev/filelock/pull/834
Release Notes
https://github.com/tox-dev/filelock/releases/tag/4.2.1
Exploit
https://github.com/tox-dev/filelock/security/advisories/GHSA-jqc4-5cvw-7w85
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