During November's Patch Tuesday, Microsoft released a security update for Internet Explorer 9 on Windows (which was rated cricital) and a security update for Windows Server (which was rated moderate). This security update, which was automatically downloaded and installed via Automatic Updates, bumped the build number for Internet Explorer 9 to 9.0.11.
The November Patch Tuesday took place on the 13th and featured this security update for Internet Explorer 9 which addresses remote code execution. "This security update resolves three privately reported vulnerabilities in Internet Explorer. The vulnerabilities could allow remote code execution if a user views a specially crafted Web page using Internet Explorer. An attacker who successfully exploited these vulnerabilities could gain the same user rights as the current user. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights," Microsoft stated in an official blog post. Most of us who have Automatic Updates enabled do not need to worry about getting this update installed as it most likely has been installed by now. If you don't have Automatic Updates enabled, check to see if you have this update available.