---
id: CVE-2026-112937
title: >-
  filelock: ReadWriteLock on the hard-link route deletes any directory another
  user renames onto its .filelock-* link directory name
summary: >-
  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…
severity: medium
cvss: 6.1
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:L'
cvssSource: cna
cwe:
  - CWE-367
vendor: tox-dev
product: filelock
affected:
  - 'filelock >= 4.1.0, < 4.2.1'
published: '2026-10-20'
updated: '2026-10-20'
sourceUpdated: '2026-10-20T14:36:28.129Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-112937'
references:
  - url: >-
      https://github.com/tox-dev/filelock/security/advisories/GHSA-jqc4-5cvw-7w85
    label: >-
      https://github.com/tox-dev/filelock/security/advisories/GHSA-jqc4-5cvw-7w85
  - url: 'https://github.com/tox-dev/filelock/pull/834'
    label: 'https://github.com/tox-dev/filelock/pull/834'
  - url: >-
      https://github.com/tox-dev/filelock/commit/5e3f2ec0c5fb17cb2635b60b2b68bc63ab81ca2d
    label: >-
      https://github.com/tox-dev/filelock/commit/5e3f2ec0c5fb17cb2635b60b2b68bc63ab81ca2d
  - url: 'https://github.com/tox-dev/filelock/releases/tag/4.2.1'
    label: 'https://github.com/tox-dev/filelock/releases/tag/4.2.1'
tags:
  - cve.org
ingestedAt: '2026-10-20T15:09:24.120Z'
---

## Overview

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

- `filelock >= 4.1.0, < 4.2.1`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.