React2Shell Vulnerability in Action - Unauthenticated RCE in React/NextJS (CTF Demo)

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In today’s video, we dive into the brand-new React2Shell vulnerability (CVE-2025-55182), a critical unauthenticated remote code execution flaw affecting React and Next.js applications. This CVSS 10.0 RCE is hitting the cybersecurity world hard — and the PerfectRoot CTF dropped a challenge using it only days after disclosure.

In this walkthrough, I break down:

- What React2Shell actually is
- How the unsafe deserialization works inside React DOM
- How to fingerprint vulnerable Next.js/React apps
- How to craft and send a working React Server Component exploit payload.
- How to safely test the vulnerability inside the PerfectRoot CTF
- Why this RCE is so dangerous (no cookies, no auth, full RCE)
- What developers and defenders must do to mitigate it

We also explore the Proof of Concept (PoC), debug payload issues, compare community payloads with TryHackMe’s working exploit, and finally achieve remote code execution to retrieve the flag.

React2Shell is a critical, unauthenticated RCE vulnerability caused by unsafe deserialization in React DOM’s server components. Any outdated React/Next.js app that supports RSCs can be compromised without authentication.

🚨 This vulnerability is already being weaponized in the wild, so make sure you update React, React DOM, and Next.js as soon as possible.

Takeaways:

- Inspecting server headers & router state tree
- Understanding the vulnerable React Server Components
- Why some payloads fail (timeouts, missing headers, sandboxing)
- Using the TryHackMe payload for reliable RCE
- Extracting the machine’s process ID and reading the flag
- Security impact and why CVE-2025-55182 is so severe

Chapters:
00:00 Introduction
00:30 ClassifiedReaction

React2Shell Information: https://react2shell.com
Rapid7 Blog: https://www.rapid7.com/blog/post/etr-react2shell-cve-2025-55182-critical-unauthenticated-rce-affecting-react-server-components/

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Disclaimer: This video is for educational purposes only. It demonstrates ethical hacking techniques to improve cybersecurity, and MRE Security is not responsible for how viewers choose to use this information.

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Видео React2Shell Vulnerability in Action - Unauthenticated RCE in React/NextJS (CTF Demo) канала MRE Security