Adobe Security Bulletin APSB10-21 describes a number of vulnerabilities affecting Adobe Reader and Acrobat. These vulnerabilities affect Reader and Acrobat 9.3.4, earlier 9.x versions, 8.2.4, and earlier 8.x versions. We recommend that users upgrade to the latest version of Reader and Acrobat.
Users on Windows and Macintosh can utilize the product's update mechanism. The default configuration is set to run automatic update checks on a regular schedule and can be manually activated by choosing Help > Check for Updates.
For more information or download links see http://www.adobe.com/support/security/bulletins/apsb10-21.html.