Today a serious issue was discovered, Internet Explorer Arbitrary Code Execution:
While browsing the internet I came across a piece of HTML code that is able to run arbitrary code while using Internet Explorer. This was tested on Windows 8.1 with Internet Explorer 11 on a fully patched system. The video demonstrates the arbitrary code execution, notepad is executed when visiting the site.
We might have another 0-day on our hands. Better avoid using Internet Explorer for a while.