Versions of Requests between v2.3.0 and v2.30.0 are vulnerable to potential
forwarding of Proxy-Authorization headers to destination servers when
following HTTPS redirects.
When proxies are defined with user info (https://user:pass@proxy:8080), Requests
will construct a Proxy-Authorization header that is attached to the request to
authenticate with the proxy.
In cases where Requests receives a redirect response, it previously reattached
the Proxy-Authorization header incorrectly, resulting in the value being
sent through the tunneled connection to the destination server. Users who rely on
defining their proxy credentials in the URL are strongly encouraged to upgrade
to Requests 2.31.0+ to prevent unintentional leakage and rotate their proxy
credentials once the change has been fully deployed.
Users who do not use a proxy or do not supply their proxy credentials through
the user information portion of their proxy URL are not subject to this
vulnerability.
