Researchers found a vulnerability in MCP inter-agent communication; five organizations including Google have confirmed it

Independent researcher Syed Anas Mohiuddin tested AI agents from organizations including Google, JP Morgan Chase, Weaviate, Rapid7, the French government's inter-ministerial digital agency, and the U.S. federal government, and found a trust gap in MCP (Model Context Protocol) inter-agent communication. The attack exploits a special form of prompt injection, targeting not the LLM but specific agents such as translation or data analysis, whose internal guardrails are often lax, causing them to pass harmful instructions down the chain to downstream agents, which execute the instructions because they explicitly trust upstream agents. Over the past five months, Google and four other organizations have confirmed the existence of such vulnerabilities, which attackers can use to spread from one agent to other internal agents within a target network, thereby stealing database contents and sensitive business and personal information.