---
id: CVE-2026-112915
title: >-
  filelock ReadWriteLock: a crafted lock database makes every acquire stall or
  hang regardless of timeout
summary: >-
  filelock is a platform-independent file lock for Python. From 3.20.4 until
  4.2.1, ReadWriteLock can open a crafted SQLite lock database without bounding
  schema and query work, allowing another local user who can replace the
  database to m…
severity: medium
cvss: 5.5
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'
cvssSource: cna
cwe:
  - CWE-400
vendor: tox-dev
product: filelock
affected:
  - 'filelock >= 3.20.4, < 4.2.1'
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-10-20T15:25:17.769823Z'
exploitAvailable: true
published: '2026-10-20'
updated: '2026-10-20'
sourceUpdated: '2026-10-20T15:25:38.592Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-112915'
references:
  - url: >-
      https://github.com/tox-dev/filelock/security/advisories/GHSA-cwqr-hh33-gh44
    label: >-
      https://github.com/tox-dev/filelock/security/advisories/GHSA-cwqr-hh33-gh44
  - 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
  - exploit-available
ingestedAt: '2026-10-20T15:09:24.125Z'
---

## Overview

filelock is a platform-independent file lock for Python. From 3.20.4 until 4.2.1, ReadWriteLock can open a crafted SQLite lock database without bounding schema and query work, allowing another local user who can replace the database to make acquisition stall or hang; versions from 3.20.4 expose this on initial per-instance opening, and versions from 3.30.0 repeat the exposure on every acquisition. This issue is fixed in version 4.2.1.

## Affected

- `filelock >= 3.20.4, < 4.2.1`

## Remediation

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