During a security audit, analysts identified unusual GET requests to a financial application where external...

During a security audit, analysts identified unusual GET requests to a financial application where external resources were fetched using numeric IPs combined with unexpected trailing characters. These inputs were not properly filtered by the system, allowing external content to be processed and embedded in server responses. The issue was traced to a feature that dynamically loads input-specified content without strict validation. Which type of attack/technique is most likely being analyzed in this scenario?