Autonomous AI trading agents suffered over $45 million in security incidents during 2026, revealing critical vulnerabilities in protocol-level memory and execution systems. Unlike typical smart contract bugs, attackers targeted the 'brain' of AI agents through memory poisoning and context manipulation. The vulnerability wasn't in trading logic but in memory layers and execution protocols where agents handle context and tool calls. OWASP's 2026 guidelines flagged memory and context poisoning as top risks, noting traditional defenses often miss them because poison appears as legitimate 'learned' knowledge. Step Finance on Solana lost approximately $40 million when compromised executive devices gave attackers access to wallets, with AI trading agents amplifying damage through excessive permissions. The breach highlighted systematic weaknesses including weak authentication, with 45.6% of teams using shared API keys, making it impossible to trace rogue agent actions.