CVE-2026-112937

filelock: ReadWriteLock on the hard-link route deletes any directory another user renames onto its .filelock-* link directory name

MEDIUM
6.1
CVSS Score
Published: October 20, 2026 at 02:36 PM UTC
Updated: October 21, 2026 at 06:05 PM UTC
1 product affected across 1 vendorFilelock

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Severity
MEDIUM6.1
Exploit prediction
EPSS 0.2%
SSVC
No known exploit

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

4.1.0 ≤ v < 4.2.1

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (4)

x_refsource_CONFIRMExploitMitigationPatchVendor Advisory
Source: cverecord
https://github.com/tox-dev/filelock/security/advisories/GHSA-jqc4-5cvw-7w85
x_refsource_MISCPatch
Source: cverecord
https://github.com/tox-dev/filelock/pull/834
x_refsource_MISCRelease Notes
Source: cverecord
https://github.com/tox-dev/filelock/releases/tag/4.2.1

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.1MEDIUMGitHub_M
Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
HIGH
Availability
LOW
Vector?

Quick Info

StatusANALYZED
CWE
CWE-367

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