Cross-site request forgery (CSRF) vulnerability on NTT EAST Hikari Denwa routers with firmware PR-400MI, RT-400MI, and RV-440MI 07.00.1006 and earlier and NTT WEST Hikari Denwa routers with firmware PR-400MI, RT-400MI, and RV-440MI 07.00.1005 and earlier allows remote attackers to hijack the authentication of arbitrary users.