From the MSRC:
Today we released Security Update MS12-063 to address limited attacks against a small number of computers through a vulnerability in Internet Explorer versions 9 and earlier. The majority of customers have automatic updates enabled and will not need to take any action because protections will be downloaded and installed automatically. For those manually updating, we encourage you to apply this update as quickly as possible.
In addition to addressing the issue described in Security Advisory 2757760, MS12-063 also resolves four privately disclosed vulnerabilities that are currently not being exploited.
For a detailed review of this security update, please join our experts Jeremy Tinder and Dustin Childs for a live webcast at noon PDT today. They will also provide answers to your questions in real-time. You can register here.
Director, Microsoft Trustworthy Computing