It's a serious issue, though that doesn't mean most people will be impacted by it. However, if you use Internet Explorer as your browser there are nonetheless two strong suggestions being made until a fix is sent by Microsoft. Using either one would eliminate the problem for now.
The first is to simply temporarily use an alternate browser if you have one, like Firefox or Chrome.
The second is to disable Adobe Flash Player in your Internet Explorer Browser for the time being. This is extremely easy to do:
Open Internet Explorer and go to Tools. Then select "Manage Addons." On the left, you'll see a column called "Add- on Types." The first listing should be called "Toolbars and Extensions" -- click on that. In the right column, look for something called either Shockwave Flash Player or Shockwave Flash Object. (It will be listed under Adobe Systems Incorporated, which likely will be listed first or near the top.) Click on it to highlight, and the click "Disable" at the bottom of the page. That's it. You'll be protected. (The downside of this option is that there could be some animated objects that won't work during your browsing. Most most of your browsing will be unaffected.)