React2Shell Ultimate - The First Autonomous Scanner for Next.js RSC RCE (CVE-2025-66478)

When the critical Remote Code Execution vulnerability in Next.js React Server Components (RSC) identified as CVE-2025-66478 was publicly disclosed, it immediately became one of the most severe supply-chain risks ever seen in the JavaScript ecosystem.

React Server Components power huge portions of modern web apps: e-commerce platforms, internal dashboards, SaaS applications, and high-traffic consumer experiences. A flaw deep in the serialization layer of RSC meant that untrusted client input could trick the server into loading arbitrary modules, resulting in full server-side RCE.

This is not a theoretical bug. This is full system compromise on thousands of internet-facing apps.

And that’s exactly why React2Shell Ultimate exists.

What is React2Shell Ultimate?

React2Shell Ultimate is an autonomous vulnerability discovery & exploitation framework created by Satyam Rastogi (@hackersatyamrastogi), designed specifically to:

• Identify endpoints susceptible to the RSC injection flaw

• Confirm the presence of the vulnerability safely

• Provide multi-mode scanning (Fast Scan, Deep Scan, Stealth Scan)

• Execute authorized exploitation using GOD MODE, enabling post-exploitation capabilities for red teams

This tool is the first dedicated scanner for CVE-2025-66478, and quickly became the red team standard for understanding the attack surface of vulnerable Next.js apps.

GitHub Repo: https://github.com/hackersatyamrastogi/react2shell-ultimate

Why CVE-2025-66478 Is a Game-Changer

1. Affects massive portions of the Next.js ecosystem

Vulnerable version range includes:

• Next.js 15.0.0 → 15.5.6

• Next.js 16.0.x initial releases

• Multiple RSC-enabled frameworks & templates

This hits production apps across finance, retail, media, healthcare, and SaaS.

2. RCE is triggered through standard RSC data flows

The payload injection occurs before any application-level sanitization can intervene.

3. SSR, streaming, Edge & Node runtimes all become potential targets

This expands the attack surface dramatically.

4. Static code review cannot reliably detect the flaw

Only dynamic testing what React2Shell Ultimate provides can confirm a vulnerable state.

How React2Shell Ultimate Works

The tool provides three key modules:

1. Recon & Endpoint Discovery

Automatically identifies:

• RSC endpoints

• API interfaces

• Hydration points

• Suspense boundaries

• Potential injection vectors

It performs smart fingerprinting to avoid noisy or destructive requests.

2. Vulnerability Detection Engine

React2Shell simulates:

• Serialized RSC payload corruption

• Module resolution abuse

• React component hydration manipulation

• Controlled template injection

If the response indicates unserialized module loading, the tool flags the endpoint as Critical.

3. GOD MODE Authorized Remote Command Execution

⚠️ GOD MODE is strictly for environments where written authorization exists.
It gives red teams the ability to fully validate exploitability by executing arbitrary commands on the server.

Capabilities include:

• Command execution

• File system interaction

• Environment variable extraction

• Persistence simulation

• SSRF & internal network probing

• Data exfiltration simulation

Every action is logged for auditability.

Perfect for Red Teaming, Bug Bounties & AppSec Engineering

React2Shell Ultimate is built with real-world offensive workflows in mind:

✔ Multi-threaded scanning

✔ Proxy & TOR support

✔ JSON & CSV export for automation pipelines

✔ Integrates with Burp, Zap, Nuclei, and CI/CD

✔ Supports black-box and grey-box assessments

It's already being integrated by major security teams into:

• CI security gates

• Offensive intelligence platforms

• Cloud perimeter scanners

• Node.js application audits

• Bug bounty toolchains

How to Patch CVE-2025-66478

Next.js maintainers released security patches across multiple versions.
Organizations should:

1. Immediately upgrade to the latest patched version

2. Rotate environment secrets (RCE means potential compromise)

3. Review logs for suspicious RSC payloads

4. Perform a full server integrity check

5. Run React2Shell Ultimate to ensure no vulnerable endpoints remain