Using untrusted user input directly in HTTP client requests like http.Get and http.NewRequest can enable server-side request forgery (SSRF). Attackers may craft malicious input that alters request destinations to access unauthorized resources. All user data must be validated against an allowlist and sanitized before usage in constructing URLs, URIs or payloads. Failing to filter dangerous values enables SSRF by allowing request destinations to be controlled. Input validation provides the primary defense by restricting inputs to known safe values. This prevents malicious users from targeting unexpected systems through client requests.