Cookie leakage, non-restricted cookie acceptance
Cookies of `foo.bar.example.com` are leaked to foo.bar. Additionally, any site can set cookies for any other site.
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.