Incorrect forwarding of sensitive headers and cookies on HTTP redirect in net/http

When following an HTTP redirect to a domain which is not a subdomain match or exact match of the initial domain, an http.Client does not forward sensitive headers such as “Authorization” or “Cookie”. For example, a redirect from foo.com to www.foo.com will forward the Authorization header, but a redirect to bar.com will not.

A maliciously crafted HTTP redirect could cause sensitive headers to be unexpectedly forwarded.