AIKIDO-2026-987609

TL;DR

The client marks a proxy CONNECT tunnel as established solely because the last request it built was a CONNECT, and keeps that mark even after the proxy rejects that CONNECT with a non-2xx status. The 401 and redirect handlers then rebuild the next request as the origin request and write it, including the origin's credentials, onto that still plaintext socket to the proxy. A 401 challenge, a 302 redirect, or an NTLM handshake run over the connection each let the proxy or a party on the path recover Basic credentials directly or capture an NTLM response that can be cracked offline. The fix records that a tunnel was actually established before using the connection as a tunnel, stops passing CONNECT responses to the origin rebuilding handlers, and closes rather than pools a connection whose CONNECT was refused.