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Severe Remote Code Execution Flaw Found in React Server Components

December 3, 2025 | 2 MINS READ

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THE THREAT

On December 3rd, a critical remote code execution vulnerability (CVE-2025-55182, CVSS 10.0) was discovered in React Server Components, affecting versions 19.0 to 19.2.0 of react-server-dom-webpack, react-server-dom-parcel, and react-server-dom-turbopack. This flaw allows attackers to exploit payload decoding in React Server Function endpoints. Users should urgently upgrade to patched versions of 19.0.1, 19.1.2, and 19.2.1. Affected frameworks include Next.js, React Router, and others. Real world exploitation has not been observed at this time, but immediate updates are required as React team noted there is a high success rate to achieve remote code execution through this vulnerability.

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Additional information

CVE-2025-55182 allows for unauthenticated remote code execution due to a flaw in the way payloads are decoded when sent to React Server Function endpoints. Even if an application does not explicitly utilize these endpoints, it remains vulnerable if it supports React Server Components. The issue was first reported by security researcher Lachlan Davidson on November 29, 2025, who highlighted the risk of attackers crafting malicious HTTP requests to exploit this flaw, thereby executing arbitrary code on the server.

In response, the React team has released critical updates as of December 3, 2025, with patched versions 19.0.1, 19.1.2, and 19.2.1 of the affected packages available for immediate download. The affected ecosystem is notably extensive, impacting frameworks and bundlers such as Next.js, React Router, Waku, @parcel/rsc, @vitejs/plugin-rsc, and rwsdk. The vulnerability underscores the importance of promptly upgrading to ensure security, particularly as frameworks dependent on React Server Components are extensively integrated in production environments. Temporary mitigations have been coordinated with a variety of hosting providers, but these should not be solely relied upon as a comprehensive solution; full resolution requires the prompt installation of the aforementioned updates.

For users of frameworks like Next.js, React Router, and Expo, specific upgrade instructions have been detailed to facilitate seamless transitions to secure versions. Next.js users, for example, are advised to update to the latest patched versions within their specific release lines or to revert to stable releases if using canary versions. Similarly, users employing React Router's unstable RSC APIs or using Expo, Waku, and other affected platforms should execute immediate updates as outlined in the detailed official instructions. This proactive approach is crucial to mitigate potential exploits arising from the vulnerability while the React team and affected parties continue to work together to validate, implement, and roll out comprehensive fixes across the affected ecosystem.

References:

[1] https://react.dev/blog/2025/12/03/critical-security-vulnerability-in-react-server-components

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