Beyond Prompt Injection: 4 OWASP Agent Security Risks Most Teams Overlook

While prompt injection dominates AI security discussions, the OWASP Top 10 for LLM Applications 2025 lists nine additional vulnerabilities that pose serious risks to AI agent deployments. Among the most critical is Excessive Agency, where agents are granted unnecessary capabilities, overly broad permissions, or allowed to take high-impact actions without human verification — often by default rather than deliberate design. Improper Output Handling is another underappreciated risk, occurring when an agent's text output is passed directly into queries, shell commands, or config files without validation, requiring no external attacker to cause harm. Security experts argue these architecture and permission-level flaws are the ones that actually cost businesses money, since they cannot be solved simply by upgrading to a better AI model. Organizations are advised to scope agent permissions tightly to each specific role and enforce authorization checks in downstream systems rather than relying on the language model itself as an access control layer.