Pattern: Unauthenticated-By-Default MCP Servers Are the Ecosystem's Dominant Attack Surface
Adversa AI·medium signal
Censys counted 12,520 internet-accessible MCP services in June, most unauthenticated, and a separate study found roughly 40% of remote MCP servers expose their tools with no authentication at all. Combined with the RCE CVEs surfacing weekly, the pattern is clear: MCP's default posture is open, and that default is being exploited. Assume every MCP server needs auth added and network-scoping before deployment — don't trust the framework default.