Adobe has released a new version of Flash, 11.6.602.171, that fixes critical security issues for Flash running on Windows and Macintosh, that could cause the application to crash and could potentially allow an attacker to take control of the affected system. Please update your systems soon.
Also, if you are running Windows and using both Internet Explorer and another web browser (i.e. Firefox, Opera or Safari), you will need to install the update twice; once using Internet Explorer and again with the other browser(s). Internet Explorer uses ActiveX for Flash, and the other browsers use a plugin.
Note that Adobe has updates available for Flash for Linux and Android, for users who have those products.
For more information and links to software downloads, see http://www.adobe.com/support/security/bulletins/apsb13-08.html