An issue was discovered in OpenNDS Captive Portal before 10.1.2. it has a do_binauth NULL pointer dereference that can be triggered with a crafted GET HTTP request with a missing client redirect query string parameter. 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. Affected OpenNDS Captive Portal before version 10.1.2 fixed infixed in OpenWrt master, OpenWrt 23.05 and OpenWrt 22.03 on28. August 2023 by updating OpenNDS to version 10.1.3.