Tenda AC20 fast_setting_wifi_set sscanf buffer overflow

A vulnerability has been found in Tenda AC20 up to 16.03.08.12. The affected element is the function sscanf of the file /goform/fast_setting_wifi_set. The manipulation of the argument timeZone leads to buffer overflow. The attack can be initiated remotely. The exploit has been disclosed to the public and may be used.