AI coding agents are installing abandoned MCP servers with known security issues

Glow Labs found that AI coding agents often install deprecated MCP servers because those package names appeared in their training data, a pattern it calls MCPhantom; in 98% of such sessions the agent chose the retired server on its own rather than because the user named it. The team identified four high-severity vulnerabilities, including a remote code execution flaw in the Puppeteer server, across Anthropic's archived reference servers, which have 17M npm downloads since July 2025 and will receive no fixes. Because these npx-launched servers appear in no dependency manifest, EDR, SCA, harness guardrails and software inventory tools miss them, leaving the endpoint as the place to detect and remove them.