undici is an HTTP/1.1 client, written from scratch for Node.js."=< undici@5.8.0" users are vulnerable to CRLF Injection on headers when using unsanitized input as request headers, more specifically, inside the "content-type" header. Example: "import { request } from 'undici' const unsanitizedContentTypeInput = 'application/json\r\n\r\nGET /foo2 HTTP/1.1' await request('http://localhost:3000, { method: 'GET', headers: { 'content-type': unsanitizedContentTypeInput }, })" The above snippet will perform two requests in a single "request" API call: 1) "http://localhost:3000/" 2) "http://localhost:3000/foo2" This issue was patched in Undici v5.8.1. Sanitize input when sending content-type headers using user input as a workaround.