LogReceiver.exe in Rockwell Automation RSLinx Enterprise CPR9 CPR9-SR1 CPR9-SR2 CPR9-SR3 CPR9-SR4 CPR9-SR5 CPR9-SR5.1 and CPR9-SR6 allows remote attackers to cause a denial of service (service outage) via a zero-byte UDP packet that is not properly handled by Logger.dll.