In firmware versions 2.7.7 and earlier, the Arris BGW210‑700 gateway fails to enforce any server‑side authentication on its /cgi-bin/*.ha management endpoints, relying solely on client‑side CSS/JavaScript gating that can be bypassed by any HTTP client. This allows unauthenticated attackers on the LAN to read sensitive configuration data, modify persistent device settings, or trigger backend diagnostic operations. The issue appears systemic across the CGI handler chain.