description: An issue was discovered in OpenNDS Captive Portal before version 10.1.2. It has a do_binauth NULL pointer dereference that be triggered with a crafted GET HTTP request with a missing User-Agent HTTP header. Triggering this issue results in crashing OpenNDS (a Denial-of-Service condition). The issue occurs when the client is about to be authenticated, and can be triggered only when the BinAuth option is set.