FastAPI + MCP: Adding Real OAuth 2.1 Auth to Your...

In the nine days after the MCP Dev Summit, NVD recorded 20 new MCP CVEs. Auth validation failures are the dominant pattern. Two examples: CVE-2025-6514 — command injection in mcp-remote, CVSS 9.6, 500,000 downloads. CVE-2026-32211 — the Azure MCP Server's SSE transport had zero authentication. Attack chain: enumerate tools, call the shell-passthrough tool (azmcp-extension-az), write a script to ~/.bashrc, exfiltrate Entra ID credentials. Full tenant takeover. Microsoft CVSS: 9.1 CRITICAL. Root c