Description
PHP through 7.0.8 does not attempt to address RFC 3875 section 4.1.18 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.
Remediation
References
Related Vulnerabilities
Oracle Database Server CVE-2006-5332 Vulnerability (CVE-2006-5332)
Moodle Exposure of Sensitive Information to an Unauthorized Actor Vulnerability (CVE-2016-0724)
WordPress Plugin One User Avatar-User Profile Picture Unspecified Vulnerability (2.3.8)
WordPress Plugin Form Builder-Create Responsive Contact Forms Cross-Site Scripting (1.9.8.4)