MCPHub authenticated horizontal IDOR: any non-admin user executes tools on other users' MCP servers (cross-tenant file read + SSRF)

MCPHub is a unified hub for centrally managing and dynamically orchestrating multiple MCP servers/APIs into separate endpoints with flexible routing strategies. Prior to version 1.0.30, MCPHub scopes non-admin users to servers they own (list views and config edits enforce ownership), but the tool-execution API does not. Any authenticated non-admin user can invoke tools on MCP servers owned by other users — servers they cannot even see in GET /api/servers. Because connected MCP servers carry real capability (filesystem, HTTP fetch, cloud APIs with the owner's keys), this is cross-tenant compromise: demonstrated arbitrary host file read (/etc/passwd, another user's secrets) and SSRF. This issue has been patched in version 1.0.30.