Microsoft Fixlet Message Severity Source
Where does TEM get the "Source Severity" for its Microsoft Fixlet Messages?
TEM uses the information published by Microsoft in the Security Bulletins, which use the rating scheme of "Low", "Moderate","Important", "Critical". See more information from Microsoft at http://www.Microsoft.com/technet/security/bulletin/rating.mspx. If the patch or update does not have a rating from Microsoft, then the Source Severity will be "<Unspecified>".
Note that depending on the operating system, some bulletins have several severity ratings for the same patch. The TEM Fixlet messages will reflect the specific severity of the specific patch version.
Windows Update uses a different rating scheme of "High priority", "Software (optional)", "Hardware (optional)". This scheme is consumer oriented and considered to be less informative for enterprise users. TEM uses the security bulletin rating to give customers the appropriate level of information.
Visit Microsoft's website for more information on the standard terminology of software updates.