Authorization headers on requests are sensitive information. When using our Curl handler, it is possible to use the
CURLOPT_HTTPAUTH option to specify an
Authorization header. On making a request which responds with a redirect to a URI with a different origin, if we choose to follow it, we should remove the
CURLOPT_USERPWD options before continuing, stopping curl from appending the
Authorization header to the new request. Previously, we would only consider a change in host. Now, we consider any change in host, port or scheme to be a change in origin.
Affected Guzzle 7 users should upgrade to Guzzle 7.4.5 as soon as possible. Affected users using any earlier series of Guzzle should upgrade to Guzzle 6.5.8 or 7.4.5. Note that a partial fix was implemented in Guzzle 7.4.2, where a change in host would trigger removal of the curl-added Authorization header, however this earlier fix did not cover change in scheme or change in port.
If you do not require or expect redirects to be followed, one should simply disable redirects all together. Alternatively, one can specify to use the Guzzle stream handler backend, rather than curl.
If you have any questions or comments about this advisory, please get in touch with us in
#guzzle on the PHP HTTP Slack. Do not report additional security advisories in that public channel, however - please follow our vulnerability reporting process.