April 2014 has been and gone. The significance of this date is that Microsoft is no longer supporting the Windows XP operating system (OS). Any security holes or bugs discovered after this date, will not be fixed.
Now although Microsoft is supporting IE8 until January 2016 they are not doing so when it is used on any unsupported OS. So let’s get back to the question: Are you still using Windows XP and Internet Explorer 8? If so, then there is now a recognised bug in it that by convincing a user to view a specially crafted HTML document (e.g., a web page or an HTML email message or attachment), an attacker may be able to execute arbitrary code on the user’s PC.
Many anti-virus companies still support their software on Windows XP, however, there is no guarantee that they will be able to prevent web-based attacks aimed at outdated versions of Internet Explorer.