[lloydsparkes]

How is this possible?

[hokkos]

It is enabled for .Net 4.5.1 as explained here : http://blogs.msdn.com/b/dotnet/archive/2014/01/22/net-4-5-1-...

[bruceboughton]

Will patches be installed on servers that have never run the application but have it deployed, such as DR servers?

The mechanism describes seems to imply they won't as Microsoft Update won't know the vulnerable assembly is sitting on the machine waiting for a failover.

[jameshart]

Same applies if I have an old build of an application which I push; it'll be vulnerable until Windows Update kicks in to patch it.