As stated in our previous MSXML post, we are already aware of targeted attacks exploiting of this vulnerability in Windows via Internet Explorer. We recommend installing the update as soon as possible in order to address this issue for Microsoft XML Core Services 3.0, 4.0, and 6.0.
If you have previously installed the Microsoft Fix it solution 50897, we recommend uninstalling it only after the update has been applied. To uninstall, please run Microsoft Fix it solution 50898.