Should I still need to say that this one is critical (well, MS already did that)?
Every time that there is a vulnerability in core Windows services, like "Server" and "Workstation", it smells like worm spirit. There is a relatively new fact that needs to be remembered these days...
Microsoft is pushing its processes to find illegal copies of Windows inside its updating system. I believe that in the last months several illegal copies that were being regularly updated are not doing that anymore. I know that personal firewalls and SoHo routers are more present, but I won't be surprised if a new worm finds more success than the last ones because of this.