Netgear R8500 v1.0.2.160, XR300 v1.0.3.78, R7000P v1.3.3.154, and R6400 v2 1.0.4.128 were discovered to contain a stack overflow via the l2tp_user_ip parameter at l2tp.cgi. This vulnerability allows attackers to cause a Denial of Service (DoS) via a crafted POST request.