Cross-site request forgery (CSRF) vulnerability on ASUS JAPAN RT-AC87U routers with firmware 3.0.0.4.378.3754 and earlier RT-AC68U routers with firmware 3.0.0.4.376.3715 and earlier RT-AC56S routers with firmware 3.0.0.4.376.3715 and earlier RT-N66U routers with firmware 3.0.0.4.376.3715 and earlier and RT-N56U routers with firmware 3.0.0.4.376.3715 and earlier allows remote attackers to hijack the authentication of arbitrary users.