Server-Side Request Forgery (SSRF)
phpBB before 3.1.11 and 3.2 before 3.2.1 is vulnerable to SSRF in the Remote Avatar function resulting allowing an attacker to perform port scanning, requesting internal content and potentially attacking such internal services via the web application.
CWE-918 - Server-Side Request Forgery (SSRF)
Server-side request forgery (SSRF) is a weakness that allows an attacker to send an arbitrary request, making it appear that the request was sent by the server. This request may bypass a firewall that would normally prevent direct access to the URL. The impact of this vulnerability can vary from unauthorized access to files and sensitive information to remote code execution.