Guzzle is an open source PHP HTTP client. In affected versions
Authorization headers on requests are sensitive information. On making a request using the
https scheme to a server which responds with a redirect to a URI with the
http scheme, we should not forward the
Authorization header on. This is much the same as to how we don't forward on the header if the host changes. Prior to this fix,
http downgrades does not result in the
Authorization header being removed, only changes to the host. Affected Guzzle 7 users should upgrade to Guzzle 7.4.4 as soon as possible. Affected users using any earlier series of Guzzle should upgrade to Guzzle 6.5.7 or 7.4.4. Users unable to upgrade may consider an alternative approach which would be to use their own redirect middleware. Alternately users may simply disable redirects all together if redirects are not expected or required.