---
id: CVE-2026-112936
title: 'filelock: ReadWriteLock follows a symlink at the lock path into SQLite'
summary: >-
  filelock is a platform-independent file lock for Python. From 3.20.4 until
  4.0.9, ReadWriteLock and AsyncReadWriteLock versions from 3.20.4 resolve the
  lock path and pass it to SQLite without rejecting a final symbolic link,
  allowing ano…
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-59
  - CWE-668
vendor: tox-dev
product: filelock
affected:
  - 'filelock >= 3.20.4, < 4.0.9'
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-10-20T16:47:15.788698Z'
exploitAvailable: true
published: '2026-10-20'
updated: '2026-10-20'
sourceUpdated: '2026-10-20T16:47:39.872Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-112936'
references:
  - url: >-
      https://github.com/tox-dev/filelock/security/advisories/GHSA-j8f7-rjxc-mr56
    label: >-
      https://github.com/tox-dev/filelock/security/advisories/GHSA-j8f7-rjxc-mr56
  - url: >-
      https://github.com/tox-dev/filelock/commit/4d45e83caf7e31f9a12fb44526bdc07f70114f04
    label: >-
      https://github.com/tox-dev/filelock/commit/4d45e83caf7e31f9a12fb44526bdc07f70114f04
  - url: 'https://github.com/tox-dev/filelock/releases/tag/4.0.9'
    label: 'https://github.com/tox-dev/filelock/releases/tag/4.0.9'
tags:
  - cve.org
  - exploit-available
ingestedAt: '2026-10-20T15:09:24.121Z'
---

## Overview

filelock is a platform-independent file lock for Python. From 3.20.4 until 4.0.9, ReadWriteLock and AsyncReadWriteLock versions from 3.20.4 resolve the lock path and pass it to SQLite without rejecting a final symbolic link, allowing another local user who can create names in the lock directory to redirect database creation and locking or split mutual exclusion between targets. This issue is fixed in version 4.0.9.

## Affected

- `filelock >= 3.20.4, < 4.0.9`

## Remediation

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