CyberRota Analysis
AI-GeneratedThe vulnerability arises from mcp-go's failure to validate the Host header in HTTP requests, allowing any request from a loopback connection to access server resources without proper authorization. This can lead to unauthorized access to sensitive data and services, as a malicious page could exploit this flaw to interact with the server as if it were local. Organizations using affected versions prior to 0.56.0 should prioritize patching to mitigate the risk of local network attacks.
Public Exploit Signal
A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.
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Original NVD Description
mcp-go accepted requests on its HTTP transports without checking the Host header. StreamableHTTPServer.ServeHTTP in server/streamable_http.go and SSEServer.ServeHTTP in server/sse.go served any request arriving over a loopback connection regardless of the host it named, and the SSE transport's cross-origin default allowed any origin. A page in a browser could therefore point a name it controlled at the loopback address and reach a server listening there, invoking tools and reading resources that the server exposed on the assumption that only local software could connect. No release before 0.56.0 validated the header on either transport; 0.56.0 adds server/http_localhost.go, which rejects a loopback-bound request carrying a host that is not a loopback name, and wires it into both transports.