Critical React Server Components RCE Vulnerability (CVE-2025-55182) Affecting React 19 & Next.js

VULNERABILITY OVERVIEW

A critical remote code execution vulnerability—CVE-2025-55182—was identified in React Server Components (RSC) affecting React 19 and several frameworks built on top of its server-rendering pipeline. Under specific conditions, specially crafted requests may cause unintended server-side code execution, allowing attackers to run arbitrary code on the underlying environment.

The vulnerability impacts multiple server-side React packages used in RSC:

• react-server-dom-parcel
• react-server-dom-webpack
• react-server-dom-turbopack

These packages shipped with React versions 19.0.0 – 19.2.0 and are embedded in popular tools such as:

• Next.js (versions ≥14.3.0-canary.77, 15.x, and early 16.x builds)
• Frameworks that integrate RSC (e.g., Vite, Parcel, Redwood, Waku, React Router integrations)

Because RSC powers server-side rendering, streaming, and data-fetching logic, any flaw in how user input is handled becomes a high-impact security risk.

RISK BREAKDOWN

• Risk: HIGH
• Impact: Remote Code Execution
• Attack Complexity: Medium
• Affected Ecosystem: React 19, Next.js, RSC-compatible frameworks

A successful exploit could allow an attacker to:

• Execute unauthorized server-side code
• Access sensitive internal data
• Modify rendering logic
• Pivot within the infrastructure
• Compromise application integrity

HOW THE ATTACK WORKS (SIMPLIFIED)

1. An attacker sends a crafted request that manipulates how React Server Components deserialize data.
2. Vulnerable RSC packages process the malicious payload without adequate validation.
3. This triggers unintended code execution inside the server rendering pipeline.
4. Applications using affected RSC versions become susceptible to remote compromise.

Although some hosting providers deployed temporary WAF mitigations, these controls cannot fully prevent exploitation because the root issue lies inside server-side library code.

AFFECTED VERSIONS

React:

• 19.0.0
• 19.1.0
• 19.1.1
• 19.2.0

Next.js:

• ≥14.3.0-canary.77
• All 15.x releases before fixes
• Early 16.x builds before patches

Other impacted ecosystems:

• Vite RSC plugins
• Parcel RSC integrations
• RedwoodJS SDK
• Waku
• Any tool embedding RSC internals

If you're using React 19 with server rendering, assume you are affected until verified otherwise.

FIXED IN

The issue has been resolved in the following versions:

React:

• 19.0.1
• 19.1.2
• 19.2.1

Next.js:

• 15.0.5
• 15.1.9
• 15.2.6
• 15.3.6
• 15.4.8
• 15.5.7
• 15.6.0-canary.58
• 16.0.7

Framework maintainers have also updated their packages to include hardened input handling and safer RSC serialization practices.

RECOMMENDATION

To protect your application from exploitation:

1. Upgrade Immediately

Install patched versions of React, Next.js, or your corresponding framework.

2. Avoid Canaries Unless Necessary

If you are using early canary builds of Next.js 14 or 15, downgrade to the latest stable 14.x release.

3. Do Not Rely on WAF Alone

Temporary mitigations help—but do not eliminate server-side RCE risks.

4. Review Server Logs

Check for suspicious RSC request patterns, malformed payloads, or deserialization anomalies.

5. Conduct a Security Assessment

RSC, SSR, and streaming pipelines are complex and should undergo periodic security testing.

IMPACT ON BUSINESSES

If your product relies on React or Next.js, especially with modern server-side rendering strategies, this vulnerability could expose your:

• Customer data
• Internal APIs
• Backend infrastructure
• Authentication workflows

Given the widespread adoption of RSC in production systems, the potential blast radius is substantial.

CONCLUSION

CVE-2025-55182 highlights the evolving threat landscape for modern JavaScript frameworks and the importance of robust secure coding and dependency management. As server-rendered ecosystems become more complex, vulnerabilities deep in rendering pipelines can have devastating consequences if left unpatched.

Agilehunt strongly recommends upgrading immediately and performing a targeted security review of any application using React Server Components.

REFERENCES

• React Security Advisory
• Next.js Security Advisory
• OWASP Guidance on Code Execution Risks

WHY CHOOSE AGILEHUNT?

With a decade of hands-on experience and deep expertise in modern JavaScript security, Agilehunt provides:

• In-depth audits of React, Next.js, and SSR architectures
• End-to-end vulnerability assessments
• Hardening guidance for RSC, API routes, streaming, and dynamic rendering
• Continuous security consultation for scaling products

Don’t wait for attackers to exploit newly disclosed vulnerabilities.

📩 Contact Agilehunt today for a free consultation and secure your application infrastructure from advanced threats.