Another serious remotely exploitable bug in Internet Explorer has cropped up, this one related to the way that IE handles a specific DLL library on pages that reference CSS files. The flaw affects IE 8, IE 7 and IE 6 running on most of the currently supported versions of Windows, including Windows 7, Windows Vista and Windows XP SP3. The bug is caused by a use-after-free error within the mshtml.dll library when processing a web page referencing a CSS (Cascading Style Sheets) file.
Source: https://threatpost.com/new-remotely-exploitable-bug-found-internet-explorer-121010/74761/