CVE-2026-55603 http-proxy-middleware: multipart/form-data field injection via unescaped CRLF in `fixRequestBody`

http-proxy-middleware is node.js http-proxy middleware. From 3.0.4 until 3.0.7 and 4.1.1, fixRequestBody is the library's documented helper for re-emitting a request body that was already consumed by a body parser. When the outgoing Content-Type is multipart/form-data, it rebuilds the body with...