Executive brief
@vitejs/plugin-rsc is a Vite plugin that handles React Server Components, used by developers building server-rendered React applications. A vulnerability in the bundled react-server-dom-webpack library allows attackers to send specially crafted HTTP requests that trigger excessive CPU usage, causing the application to become unresponsive and denying service to legitimate users.
Technical details
The vulnerability is a resource exhaustion issue (CWE-770) in the react-server-dom-webpack library vendored by @vitejs/plugin-rsc versions prior to 19.2.6. When a specially crafted HTTP request is deserialized by an affected App Router Server Function endpoint, it triggers excessive CPU consumption without any rate limiting or resource constraints. The attack requires only network access with no authentication or user interaction; an attacker can remotely send malicious requests to trigger denial of service. The fix is available in @vitejs/plugin-rsc 0.5.26 and later, which updates the vendored react-server-dom-webpack to a patched version.
Affected products
- Vitejs plugin-rsc prior to 0.5.26
Timeline
- 2026-05-07: disclosed
- 2026-05-07: patched: Available in @vitejs/plugin-rsc 0.5.26 and later