Adobe has release updates for its Reader product. These updates address critical vulnerabilities that could cause the program to crash and allow an attacker to gain control of the system. Adobe recommend that users update to Adobe Reader 9.1. Updates are currently available for Windows and Macintosh versions. Adobe plans to release updates for the Linux version by March 24th. For more information go to http://www.adobe.com/support/security/bulletins/apsb09-04.html.
Adobe Reader 9.1 (all versions) - http://get.adobe.com/reader/