FlowIntel external reference URL probe allows server-side request forgery

FlowIntel up to version 3.3.0 contains a server-side request forgery (SSRF) vulnerability in the external reference URL probe functionality in app/case/task.py. An attacker who can submit an external reference URL can cause the application server to issue an HTTP HEAD request to an attacker-specified destination. Due to insufficient validation of the URL scheme and resolved destination address, affected versions may allow requests to loopback, link-local, private, reserved, or other restricted network resources, potentially enabling interaction with internal services or cloud metadata endpoints from the server's network context.