An issue was discovered in InspIRCd 2 before 2.0.28 and 3 before 3.3.0. The mysql module contains a NULL pointer dereference when built against mariadb-connector-c 3.0.5 or newer. When combined with the sqlauth or sqloper modules, this vulnerability can be used for remote crashing of an InspIRCd server by any user able to connect to a server.