To fix some bugs and loop hole found in Internet Explorer 9 Microsoft has released KB2559049 patch update for all users.
This security update resolves five privately reported vulnerabilities and two publicly disclosed vulnerabilities in Internet Explorer. The most severe vulnerabilities could allow remote code execution if a user views 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 impacted than users who operate with administrative user rights.
This security update is rated Critical for Internet Explorer 6 on Windows clients, and for Internet Explorer 7, Internet Explorer 8, and Internet Explorer 9; and Important for Internet Explorer 6 on Windows servers.
You can either check for update via About Internet Explorer and the click on KB2559049 to update or use below link :-
Download Link for Windows 7
Download Link for Windows 7 (64-bit)
Download Link for Windows Vista
Download Link for Windows Vista (64-bit)
Download Link for Windows Server 2008
Download Link for Windows Server 2008 (64-bit)
Download Link for Windows Server 2008 R2 (64-bit)