When Your AI Agent Goes Rogue: The Hidden Risk of Excessive Agency
In Oct 2025, a malicious code in AI agent server stole thousands of emails with just one line of code. The package, called postmark-mcp, looked completely legitimate. It worked perfectly for 15 versions. Then, on version 1.0.16, the developer slipped in a tiny change. every outgoing email now included a hidden BCC to an attacker-controlled address. By the time anyone noticed, roughly 300 organizations had been compromised. Password resets, invoices, customer data, internal correspondence.