Adobe has released an out of cycle update for their Flash Player. A recently discovered vulnerability in the software allows malicious code to be injected and give remote access to the sender.
Users of Google Chrome will have the update applied automatically the next time the program is opened and connected to the Internet. The same is true for users with Internet Explorer 10 and above.
If you are not sure which browser have just open you browser and type in the URL bar "www.adobe.com". Then go to the right look for a tab labeled "download, then click "Flash Player". Follow the onscreen instructions. If your browser has already updated itself, it will notify you. I would also recommend updating your "Adobe Reader", and "Adobe Air" programs from the same download tab.
Read about it from the official Adobe release: http://helpx.adobe.com/security/products/flash-player/apsb14-04.html