Multiple cross-site request forgery (CSRF) vulnerabilities in goform/RgDdns in ARRIS (formerly Motorola) SBG901 SURFboard Wireless Cable Modem allow remote attackers to hijack the authentication of administrators for requests that (1) change the dns service via the DdnsService parameter, (2) change the username via the DdnsUserName parameter, (3) change the password via the DdnsPassword parameter, or (4) change the host name via the DdnsHostName parameter.