“On November 29th, Lachlan Davidson reported a security vulnerability in React that allows unauthenticated remote code execution by exploiting a flaw in how React decodes payloads sent to React Server Function endpoints.
Even if your app does not implement any React Server Function endpoints it may still be vulnerable if your app supports React Server Components.”
https://react.dev/blog/2025/12/03/critical-security-vulnerability-in-react-server-components
The vulnerability is present in versions 19.0, 19.1.0, 19.1.1, and 19.2.0 of:
A fix was introduced in versions 19.0.1, 19.1.2, and 19.2.1. If you are using any of the above packages please upgrade to any of the fixed versions immediately.
If your app’s React code does not use a server, your app is not affected by this vulnerability. If your app does not use a framework, bundler, or bundler plugin that supports React Server Components, your app is not affected by this vulnerability.