Package Instance

Cross-domain cookie leakage in Guzzle
### Impact

Previous version of Guzzle contain a vulnerability with the cookie middleware. The vulnerability is that it is not checked if the cookie domain equals the domain of the server which sets the cookie via the `Set-Cookie` header, allowing a malicious server to set cookies for unrelated domains. For example an attacker at `www.example.com` might set a session cookie for `api.example.net`, logging the Guzzle client into their account and retrieving private API requests from the security log of their account.

Note that our cookie middleware is disabled by default, so most library consumers will not be affected by this issue. Only those who manually add the cookie middleware to the handler stack or construct the client with `['cookies' => true]` are affected. Moreover, those who do not use the same Guzzle client to call multiple domains and have disabled redirect forwarding are not affected by this vulnerability.

### Patches

Affected Guzzle 7 users should upgrade to Guzzle 7.4.3 as soon as possible. Affected users using any earlier series of Guzzle should upgrade to Guzzle 6.5.6 or 7.4.3.

### Workarounds

If you do not need support for cookies, turn off the cookie middleware. It is already off by default, but if you have turned it on and no longer need it, turn it off.

### References

* [RFC6265 Section 5.3](https://datatracker.ietf.org/doc/html/rfc6265#section-5.3)
* [RFC9110 Section 15.4](https://www.rfc-editor.org/rfc/rfc9110.html#name-redirection-3xx)

### For more information

If you have any questions or comments about this advisory, please get in touch with us in `#guzzle` on the [PHP HTTP Slack](https://php-http.slack.com/). Do not report additional security advisories in that public channel, however - please follow our [vulnerability reporting process](https://github.com/guzzle/guzzle/security/policy).

Failure to strip the Cookie header on change in host or HTTP downgrade
### Impact

`Cookie` 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, or on making a request to a server which responds with a redirect to a a URI to a different host, we should not forward the `Cookie` header on. Prior to this fix, only cookies that were managed by our cookie middleware would be safely removed, and any `Cookie` header manually added to the initial request would not be stripped. We now always strip it, and allow the cookie middleware to re-add any cookies that it deems should be there.

### Patches

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.

### Workarounds

An alternative approach would be to use your own redirect middleware, rather than ours, if you are unable to upgrade. If you do not require or expect redirects to be followed, one should simply disable redirects all together.

### References

* [RFC9110 Section 15.4](https://www.rfc-editor.org/rfc/rfc9110.html#name-redirection-3xx)

### For more information

If you have any questions or comments about this advisory, please get in touch with us in `#guzzle` on the [PHP HTTP Slack](https://php-http.slack.com/). Do not report additional security advisories in that public channel, however - please follow our [vulnerability reporting process](https://github.com/guzzle/guzzle/security/policy).

Fix failure to strip Authorization header on HTTP downgrade
### Impact

`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, `https` to `http` downgrades did not result in the `Authorization` header being removed, only changes to the host.

### Patches

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.

### Workarounds

An alternative approach would be to use your own redirect middleware, rather than ours, if you are unable to upgrade. If you do not require or expect redirects to be followed, one should simply disable redirects all together.

### References

* [RFC9110 Section 15.4](https://www.rfc-editor.org/rfc/rfc9110.html#name-redirection-3xx)

### For more information

If you have any questions or comments about this advisory, please get in touch with us in `#guzzle` on the [PHP HTTP Slack](https://php-http.slack.com/). Do not report additional security advisories in that public channel, however - please follow our [vulnerability reporting process](https://github.com/guzzle/guzzle/security/policy).

Improper Access Control
PHP does not attempt to address RFC section namespace conflicts and therefore does not protect applications from the presence of untrusted client data in the `HTTP_PROXY` environment variable, which might allow remote attackers to redirect an application's outbound HTTP traffic to an arbitrary proxy server via a crafted Proxy header in an HTTP request, as demonstrated by (1) an application that makes a getenv('HTTP_PROXY') call or (2) a CGI configuration of PHP, aka an `httpoxy` issue.