Next.js is a React framework for building full-stack web applications. In versions starting from 13.0 to before 14.2.30 and 15.0.0 to before 15.2.2, Next.js may have allowed limited source code exposure when the dev server was running with the App Router enabled. The vulnerability only affects local development environments and requires the user to visit a malicious webpage while npm run dev is active. This issue has been patched in versions 14.2.30 and 15.2.2.
The product uses a WebSocket, but it does not properly verify that the source of data or communication is valid.
WebSockets provide a bi-directional low latency communication (near real-time) between a client and a server. WebSockets are different than HTTP in that the connections are long-lived, as the channel will remain open until the client or the server is ready to send the message, whereas in HTTP, once the response occurs (which typically happens immediately), the transaction completes. A WebSocket can leverage the existing HTTP protocol over ports 80 and 443, but it is not limited to HTTP. WebSockets can make cross-origin requests that are not restricted by browser-based protection mechanisms such as the Same Origin Policy (SOP) or Cross-Origin Resource Sharing (CORS). Without explicit origin validation, this makes CSRF attacks more powerful.