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Glossary

Tool Call Hijacking

Reviewed 9 April 2026 Canonical definition

Tool call hijacking is an attack where a malicious actor intercepts or manipulates an agent's tool call before it reaches the intended server — redirecting it to a different endpoint, modifying the parameters, or injecting additional actions. It exploits insufficiently authenticated transport channels and can result in data theft, privilege escalation, or unintended side effects in downstream systems.