CVE-2026-86414: curl: curl: leaking host credentials to HTTP proxy

Severity: Critical

CVSS Score: 9.1

An HTTP proxy can trick libcurl into sending the origin's credentials (Basic password, or a Negotiate/Kerberos ticket) to the proxy itself, by answering the `CONNECT` tunnel request with 401 `WWW-Authenticate:` instead of the expected 407 `Proxy-Authenticate:`.