A flaw was found in Go's net/http/cookiejar standard library package. When following an HTTP redirect to a domain that is not a subdomain match or an 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.