The vulnerability is a classic Server-Side Request Forgery (SSRF) located in the network connectivity check feature. The root cause is a lack of input validation on the targetIp and targetPort parameters. An attacker can make a GET request to the /server/checkConnectivity endpoint, which is handled by ServerController.checkConnectivity. This controller function takes the user-supplied IP and port and passes them directly to PingPongUtils.checkConnectivity. Inside this utility function, the code creates a new java.net.Socket with the provided arguments, causing the server to initiate a connection to an arbitrary destination. This can be exploited by an attacker to scan internal networks, access internal services, or exfiltrate data to an external server.