---
id: CVE-2026-112950
title: >-
  Vitest: Windows backslash traversal bypasses the @vitest/mocker redirect
  allowlist fix
summary: >-
  Vitest is a Vite-native testing framework for JavaScript and TypeScript
  projects. From 4.1.11 until 4.1.12 and 5.0.3, isFileLoadingAllowed and the
  filesystem read interpret backslashes differently on Windows in
  packages/mocker/src/node/i…
severity: medium
cvss: 5.9
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N'
cvssSource: cna
cwe:
  - CWE-22
vendor: vitest-dev
product: vitest
affected:
  - 'vitest >= 4.1.11, < 4.1.12'
  - 'vitest >= 5.0.0-rc.2, < 5.0.3'
  - 'mocker >= 4.1.11, < 4.1.12'
  - 'mocker >= 5.0.0-rc.2, < 5.0.3'
published: '2026-10-20'
updated: '2026-10-20'
sourceUpdated: '2026-10-20T15:21:32.396Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-112950'
references:
  - url: >-
      https://github.com/vitest-dev/vitest/security/advisories/GHSA-xp26-3454-mjgp
    label: >-
      https://github.com/vitest-dev/vitest/security/advisories/GHSA-xp26-3454-mjgp
  - url: >-
      https://github.com/vitest-dev/vitest/commit/15cc006aa9f8683dc5f7e895d011fa7dc751ce35
    label: >-
      https://github.com/vitest-dev/vitest/commit/15cc006aa9f8683dc5f7e895d011fa7dc751ce35
  - url: >-
      https://github.com/vitest-dev/vitest/commit/b825313243dc55757e8d7c0f9e7a792135e13473
    label: >-
      https://github.com/vitest-dev/vitest/commit/b825313243dc55757e8d7c0f9e7a792135e13473
  - url: 'https://github.com/vitest-dev/vitest/releases/tag/v4.1.12'
    label: 'https://github.com/vitest-dev/vitest/releases/tag/v4.1.12'
  - url: 'https://github.com/vitest-dev/vitest/releases/tag/v5.0.3'
    label: 'https://github.com/vitest-dev/vitest/releases/tag/v5.0.3'
tags:
  - cve.org
ingestedAt: '2026-10-20T16:10:53.314Z'
---

## Overview

Vitest is a Vite-native testing framework for JavaScript and TypeScript projects. From 4.1.11 until 4.1.12 and 5.0.3, isFileLoadingAllowed and the filesystem read interpret backslashes differently on Windows in packages/mocker/src/node/interceptorPlugin.ts. When a client can reach the Vite dev server on Windows and register a redirect mock containing backslash traversal, POSIX joining preserves a Windows backslash traversal that the later filesystem read interprets as a path separator, so the client can read a file outside server.fs.allow that the Vitest process can access. This issue is fixed in versions 4.1.12 and 5.0.3.

## Affected

- `vitest >= 4.1.11, < 4.1.12`
- `vitest >= 5.0.0-rc.2, < 5.0.3`
- `mocker >= 4.1.11, < 4.1.12`
- `mocker >= 5.0.0-rc.2, < 5.0.3`

## Remediation

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