This indicates a vulnerability in Nessus Vulnerability Scanner. The vulnerability is caused by an error in the "addsetConfig()" method within the scan.dll ActiveX control. It allows remote attackers to execute arbitrary code by invoking the addsetConfig method with malicious input.
Nessus Vulnerability Scanner version 3.0.6 and prior.
System compromise, remote code execution.
Currently we are not aware of any official supplied fix for this issue.