As you know Microsoft pushed out first update for IE9 couple of months before and yesterday they pushed out Internet Explorer version 9.0.2. This IE9 security update will resolve five vulnerabilities that allow remote code execution if a user visits a malicious, specially crafted Web page using Internet Explorer. This security update is rated Critical and more information is available here.
Internet Explorer 9.0.2 is currently available through Windows Update as the August 2011 Cumulative Security Update for Internet Explorer, and IE 9.0.1 was also served automatically to users through WU as the June 2011 Cumulative Security Update for Internet Explorer.
Only users running Windows 7 SP1, Windows 7 RTM and Windows Vista SP2, as well as their server equivalents, will be able to update to IE 9.0.2