CVE-2018-20060

urllib3 before version 1.23 does not remove the Authorization HTTP header when following a cross-origin redirect (i.e., a redirect that differs in host, port, or scheme). This can allow for credentials in the Authorization header to be exposed to unintended hosts or transmitted in cleartext.

Mitigation

Use retries=urllib3.Retry(redirect=0) when performing requests if you do not need redirection and handle the redirects manually if you need them.