The DI-7400G+ router has a command injection vulnerability, which allows attackers to execute arbitrary commands on the device. The sub_478D28 function in in mng_platform.asp, and sub_4A12DC function in wayos_ac_server.asp of the jhttpd program, with the parameter ac_mng_srv_host.
https://www.dlink.com/en/security-bulletin/
https://www.dlink.com.cn/techsupport/ProductInfo.aspx?m=DI-7400G%2B