According to the security bulletin at Adobe:
Critical vulnerabilities have been identified in Adobe Reader 9.2 and Acrobat 9.2 for Windows, Macintosh and UNIX, and Adobe Reader 8.1.7 and Acrobat 8.1.7 for Windows and Macintosh. These vulnerabilities could cause the application to crash and could potentially allow an attacker to take control of the affected system.
If you are using Adobe Reader 9.2 or Reader 8.1.7, it is highly recommended that you apply the patch. You can download Adobe Reader 9.3 or Reader 8.2 from the official download page.