Adobe just released an out-of-band update (APSB14-04) to their Flash player, which fixes a vulnerability (CVE-2014-0497) that is being exploited in the wild. Flash version 12 and 11 is affected on Windows and Mac OS X and Flash version 11 is affected on the Linux platform. Users of Google Chrome and Microsoft Internet Explorer 10 and 11 will get their updates automatically through a browser update, but should still verify if they need to update Flash on the operating system itslef as well, if a browser is installed that does not bring its own version of Flash (for example, Safari on Mac OS X, Firefox or older versions of IE).
We recommend installing the update as quickly as possible. Adobe Flash is widely installed and used in the majority of webpages to provide active content: videos and games. It is difficult to restrict its use and users cannot be expected to present any obstacle to an attack that in embedded in a well-known, trusted web-page.
If you are a Firefox user, take a look at the latest release v27. While it does not address this latest Adobe Flash problem, Mozilla fixed 13 vulnerabilities, including four critical vulnerabilities. Recommended to install as quickly as possible as well.