Tenda AC10 version US_AC10V4.0si_V16.03.10.13_cn was discovered to contain a stack overflow via the firewallEn parameter in the function SetFirewallCfg.
The product writes data past the end, or before the beginning, of the intended buffer.
A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).