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The vulnerability in React Server Components stems from a flaw in the serialization process during server-side rendering. In affected versions, when React Server Components are rendered on the server, the serialization logic incorrectly handles certain internal data structures. This bug can cause the serialized output sent to the client to include sensitive debug information, such as file system paths or fragments of source code. The issue occurs under specific conditions, particularly when component rendering encounters errors or when serializing components with dynamic imports. The leak happens because internal module references and error details are not properly sanitized before being included in the response payload. This exposure is contingent on using React Server Components in a server environment, like with frameworks such as Next.js. Attackers can trigger this by crafting requests that cause the server to render components in a way that exploits the serialization bug. The leaked data appears in the HTTP responses, potentially revealing application source code. The patches address this by correcting the serialization function to strip all internal metadata and ensure only safe, intended data is transmitted.
Platform: React
Version: 19.0.0-19.2.1
Vulnerability: Source code exposure
Severity: Moderate
date: Dec 11, 2025
Prediction: Patched Dec 11, 2025
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npm list react
npm install [email protected]
// Example vulnerable server component pattern
export default function MyComponent() {
// Internal module paths might leak
const data = require('internal/module');
return
<div>{data}</div>
;
}
How Exploit:
Craft requests triggering serialization errors to leak source code in HTTP responses.
Protection from this CVE:
Update to patched versions: 19.0.2, 19.1.3, 19.2.2.
Impact:
Source code disclosure, intellectual property theft, security breaches.
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Sources:
Reported By: github.com
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