The Incident: What Happened to Ekubo? On May 6, 2026, Ekubo Protocol (a major liquidity layer) faced a $1.4M exploit. While the core liquidity remained safe, the vulnerability resided in the EVM extension router. The attacker exploited a flaw in the Payment Callback logic, manipulating token transfers from users who had granted maximum approvals to the contract. This wasn't a flaw in the AMM math itself, but a failure in access control and state validation during cross-chain interactions. The Solution: Active Invariant Monitoring Post-mortem audits are great, but they don't bring back the funds. As a security researcher, I believe the future of DeFi security lies in Active Sentinel Agents—tools that monitor protocol invariants in real-time and trigger defensive actions. To address this, I've updated my project, Sentinel-Rhea, to support multi-chain monitoring (EVM + Starknet). The Strategy Our agent doesn't just check if a hack happened; it checks if the rules of the protocol are still being followed.…