An issue was discovered on Tenda AC6 V1.0 V15.03.05.19_multi_TD01, AC9 V1.0 V15.03.05.19(6318)_CN, AC9 V3.0 V15.03.06.42_multi, AC15 V1.0 V15.03.05.19_multi_TD01, and AC18 V15.03.05.19(6318_)_CN devices. There is a buffer overflow vulnerability in the router's web server -- httpd. While processing the /goform/setcfm funcpara1 parameter for a POST request, a value is directly used in a sprintf to a local variable placed on the stack, which overwrites the return address of a function. An attacker can construct a payload to carry out arbitrary code execution attacks.