The D-Link DIR-816 A2 1.11 router only checks the random token when authorizing a goform request. An attacker can get this token from dir_login.asp and use an API URL /goform/form2userconfig.cgi to edit the system account without authentication.
https://github.com/PAGalaxyLab/VulInfo/blob/master/D-Link/DIR-816/edit_sys_account/README.md