- Lab
- Security
CVE-2025-29927 Next.js Middleware: Emulation and Detection
In this lab, you will emulate, detect, and implement protections against an authorization bypass vulnerability in Next.js middleware, as described in CVE-2025-29927.
Path Info
Table of Contents
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Challenge
Getting Started in the Lab Environment
Here are the initial instructions and explanation of the lab environment. Read this while your environment is busy creating itself from nothing. Yes, this violates physics; we know. How fun!
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Challenge
Emulate
In this challenge, you will emulate the Next.js authorization bypass exploit in a test environment.
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Challenge
Detect
In this challenge, you will detect the authorization bypass by reviewing Nginx logs created with a new custom output containing the affected header.
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Challenge
Protect
In this challenge, you will protect against the vulnerability by blocking specific requests with the affected header to the application.
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Challenge
The Last Challenge
Welcome to the final challenge! This is your last chance to experiment in the environment. Clicking Finish Lab will end this little world that flittered into existence just for you.
What's a lab?
Hands-on Labs are real environments created by industry experts to help you learn. These environments help you gain knowledge and experience, practice without compromising your system, test without risk, destroy without fear, and let you learn from your mistakes. Hands-on Labs: practice your skills before delivering in the real world.
Provided environment for hands-on practice
We will provide the credentials and environment necessary for you to practice right within your browser.
Guided walkthrough
Follow along with the author’s guided walkthrough and build something new in your provided environment!
Did you know?
On average, you retain 75% more of your learning if you get time for practice.