30 CVEs. 60 days. 437,000 compromised downloads. The Model Context Protocol went from “promising open standard” to “active threat surface” faster than anyone predicted.

Between January and February 2026, security researchers filed over 30 CVEs targeting MCP servers, clients, and infrastructure. The vulnerabilities ranged from trivial path traversals to a CVSS 9.6 remote code execution flaw in a package downloaded nearly half a million times. And the root causes were not exotic zero-days — they were missing input validation, absent authentication, and blind trust in tool descriptions.

If you are running MCP servers in production — or even just experimenting with them in Claude Code or Cursor — this article is your field guide to what went wrong and how to protect yourself.