CVE-2025-43864 PoC — React Router allows a DoS via cache poisoning by forcing SPA mode

Source

https://github.com/pouriam23/DoS-via-cache-poisoning-by-forcing-SPA-mode-CVE-2025-43864-

Associated Vulnerability

Title:React Router allows a DoS via cache poisoning by forcing SPA mode (CVE-2025-43864)
Description:React Router is a router for React. Starting in version 7.2.0 and prior to version 7.5.2, it is possible to force an application to switch to SPA mode by adding a header to the request. If the application uses SSR and is forced to switch to SPA, this causes an error that completely corrupts the page. If a cache system is in place, this allows the response containing the error to be cached, resulting in a cache poisoning that strongly impacts the availability of the application. This issue has been patched in version 7.5.2.

Readme

# Welcome to React Router!

A modern, production-ready template for building full-stack React applications using React Router.

[![Open in StackBlitz](https://developer.stackblitz.com/img/open_in_stackblitz.svg)](https://stackblitz.com/github/remix-run/react-router-templates/tree/main/default)

## Features

- 🚀 Server-side rendering
- ⚡️ Hot Module Replacement (HMR)
- 📦 Asset bundling and optimization
- 🔄 Data loading and mutations
- 🔒 TypeScript by default
- 🎉 TailwindCSS for styling
- 📖 [React Router docs](https://reactrouter.com/)

## Getting Started

### Installation

Install the dependencies:

```bash
npm install
```

### Development

Start the development server with HMR:

```bash
npm run dev
```

Your application will be available at `http://localhost:5173`.

## Building for Production

Create a production build:

```bash
npm run build
```

## Deployment

### Docker Deployment

To build and run using Docker:

```bash
docker build -t my-app .

# Run the container
docker run -p 3000:3000 my-app
```

The containerized application can be deployed to any platform that supports Docker, including:

- AWS ECS
- Google Cloud Run
- Azure Container Apps
- Digital Ocean App Platform
- Fly.io
- Railway

### DIY Deployment

If you're familiar with deploying Node applications, the built-in app server is production-ready.

Make sure to deploy the output of `npm run build`

```
├── package.json
├── package-lock.json (or pnpm-lock.yaml, or bun.lockb)
├── build/
│   ├── client/    # Static assets
│   └── server/    # Server-side code
```

## Styling

This template comes with [Tailwind CSS](https://tailwindcss.com/) already configured for a simple default starting experience. You can use whatever CSS framework you prefer.

---

Built with ❤️ using React Router.

File Snapshot


 [4.0K]  /data/pocs/3237691f97e8328e1b181e459eaa452ec8b3cd03
├── [4.0K]  app
│   ├── [ 300]  app.css
│   ├── [1.7K]  root.tsx
│   ├── [4.0K]  routes
│   │   └── [ 315]  home.tsx
│   ├── [ 134]  routes.ts
│   └── [4.0K]  welcome
│       ├── [6.0K]  logo-dark.svg
│       ├── [6.0K]  logo-light.svg
│       └── [4.1K]  welcome.tsx
├── [ 599]  Dockerfile
├── [ 814]  package.json
├── [230K]  package-lock.json
├── [4.0K]  public
│   └── [ 15K]  favicon.ico
├── [ 205]  react-router.config.ts
├── [1.8K]  README.md
├── [ 605]  tsconfig.json
└── [ 280]  vite.config.ts

4 directories, 15 files

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