Well seems this exploit provides an escalation of privileges to an ALREADY authenticated user.
eWeek article below:
Vista Exploit Surfaces on Russian Hacker Site
I can't yet tell how this is going to effect the adoption of Microsofts self proclaimed "Most secure operating system yet"
Since it is not publically available yet the threat seems low, but if businesses weren't leery enough of adoption yet then this might help seal it. But who knows, definately not me!!