CVE-2026-42211

Updated on 02 Jun 2026

Severity

8.1 High severity

Details

CVSS score
8.1
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Overview

About vulnerability

When using React Router v7 in [Framework Mode](https://reactrouter.com/start/modes#framework), there exists a combination of steps that could potentially allow unauthorized RCE through external requests. This first requires the application code to have an existing prototype pollution vulnerability. This can be leveraged into a 2-step attack in which the second step can trigger unauthorized RCE on the remote server.

> [!NOTE] > This does not impact your React Router application if you are using [Declarative Mode](https://reactrouter.com/start/modes#declarative) (<BrowserRouter>) or [Data Mode](https://reactrouter.com/start/modes#data) (createBrowserRouter/<RouterProvider>).

Details

Affected product:
React , remix
Affected packages:
@remix-run/react @ 2.17.5 (+81 more)

Fixes