Be aware of a security issue for Internet Explorer 6 to 11.
The full information about the bug from Microsoft can be found here. Note there is no fix for Windows XP. If you are still running it, get off it. Until a fix is released, there are mitigation strategies you can apply.
The following article from Microsoft covers off some strategies to help protect your environment.
https://technet.microsoft.com/en-US/library/security/2963983