Some time ago I wrote about a serious problem which is affecting DNS service, to be more specific management interface available through RPC. As DNS is one of heavily used service in Active Directory networks this is real problem.
With this month's security patches we can get fix for this problem described in MS07-029 security bulletin. This is one of serious flaws so my advice would be to test it in a test lab and apply on production as soon as it is possible according to Your patch deployment plan.
In this month total number of seven critical bulletins were released so it looks like it is wise to get to know with them and apply in our networks. All information about this month's security patches are on Technet site.