The April 2012 Cumulative Security Update for Internet Explorer is now available via Windows Update. This security update resolves five privately reported vulnerabilities in Internet Explorer. The most severe vulnerabilities could allow remote code execution if a user visits a specially crafted Web page using Internet Explorer. An attacker who successfully exploited any of these vulnerabilities could gain the same user rights as the local user. Users whose accounts are configured to have fewer user rights on the system could be less affected than users who operate with administrative user rights.
This security update is rated Critical for Internet Explorer 6, Internet Explorer 7, Internet Explorer 8, and Internet Explorer 9 on Windows clients and Moderate for Internet Explorer 6, Internet Explorer 7, Internet Explorer 8, and Internet Explorer 9 on Windows servers. For more information, see the full bulletin.
Source: IEBlog