---
id: CVE-2026-112941
title: >-
  filelock: SoftReadWriteLock follows a lock tree swapped in after its first
  acquire and writes lock records into directories of the user running the lock
summary: >-
  filelock is a platform-independent file lock for Python. From 4.1.0 until
  4.2.1, SoftReadWriteLock and AsyncSoftReadWriteLock cache a successful check
  of the <path>.rw lock tree and resolve its names again during later record
  operations,…
severity: low
cvss: 3.3
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N'
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: '2026-10-20T14:43:18.060Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-112941'
references:
  - url: >-
      https://github.com/tox-dev/filelock/security/advisories/GHSA-wfhq-q4j2-c37m
    label: >-
      https://github.com/tox-dev/filelock/security/advisories/GHSA-wfhq-q4j2-c37m
  - url: 'https://github.com/tox-dev/filelock/pull/842'
    label: 'https://github.com/tox-dev/filelock/pull/842'
  - url: >-
      https://github.com/tox-dev/filelock/commit/bfa066d65a1ba9106f86ee9d027f7588b9c77e03
    label: >-
      https://github.com/tox-dev/filelock/commit/bfa066d65a1ba9106f86ee9d027f7588b9c77e03
  - 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: '2026-10-20T15:09:24.117Z'
---

## Overview

filelock is a platform-independent file lock for Python. From 4.1.0 until 4.2.1, SoftReadWriteLock and AsyncSoftReadWriteLock cache a successful check of the <path>.rw lock tree and resolve its names again during later record operations, allowing another local user who can replace that tree after the first acquisition to redirect lock-record writes into directories writable by the lock user. 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.