CVE-2026-85720: AsyncHttpClient sends origin credentials to the proxy on the plaintext CONNECT request

When a request uses an HTTP proxy to reach an HTTPS origin, the client opens the tunnel with a plaintext CONNECT sent to the proxy before any TLS exists. On affected versions the origin’s preemptive credentials were added to that CONNECT. A Basic realm sent Authorization: Basic base64(user:pass) to the proxy in the clear, and NTLM, SPNEGO or Kerberos realms sent their token. The proxy, and anyone who can read the client to proxy hop, saw credentials that were meant only for the origin.