An unauthenticated remote attacker can send data to RsvcHost.exe listening on TCP port 5241 to add entries in the FactoryTalk Diagnostics event log. The attacker can specify long fields in the log entry, which can cause an unhandled exception in wcscpy_s() if a local user opens FactoryTalk Diagnostics Viewer (FTDiagViewer.exe) to view the log entry. Observed in FactoryTalk Diagnostics 6.11. All versions of FactoryTalk Diagnostics are affected.