Triangle MicroWorks SCADA Data Gateway 2.50.0309 through 3.00.0616, DNP3 .NET Protocol components 3.06.0.171 through 3.15.0.369, and DNP3 C libraries 3.06.0000 through 3.15.0000 allow physically proximate attackers to cause a denial of service (infinite loop) via crafted input over a serial line.