Server-Side Request Forgery (SSRF)
A vulnerability exists in phpBB <v3.2.10 and <v3.3.1 which allowed remote image dimensions check to be used to SSRF.
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.