PYSEC-2026-3387 Tornado: Authorization header forwarded across cross-origin redirects in SimpleAsyncHTTPClient

Summary When SimpleAsyncHTTPClient follows a 3xx redirect, it shallow-copies the original HTTPRequest, rewrites the URL, decrements maxredirects, and removes only the Host header. It does not clear Authorization, authusername, authpassword, or authmode when the redirect target changes origin. As ...