A critical vulnerability has been identified in Adobe Reader 9.3 for Windows, Macintosh and UNIX, Adobe Acrobat 9.3 for Windows and Macintosh, and Adobe Reader 8.2 and Acrobat 8.2 for Windows and Macintosh. This vulnerability could subvert the domain sandbox and make unauthorized cross-domain requests, Adobe said. In addition, a critical vulnerability has been identified that could cause the application to crash and could potentially allow an attacker to take control of the affected system.

Adobe recommends users of Adobe Reader 9.3 and earlier versions for Windows, Macintosh and UNIX update to Adobe Reader 9.3.1. (For Adobe Reader users on Windows and Macintosh who cannot update to Adobe Reader 9.3.1, Adobe has provided the Adobe Reader 8.2.1 update.)

The company also recommends users of Adobe Acrobat 9.3 and earlier versions for Windows and Macintosh update to Adobe Acrobat 9.3.1.

Finally users of Acrobat 8.2 and earlier versions for Windows and Macintosh should update to Acrobat 8.2.1.

Users can utilize the product's automatic update facility.

Adobe Reader users on Windows can find the appropriate update here:
http://www.adobe.com/support/downloads/product.jsp?product=10&platform=Windows.

Adobe Reader users on Macintosh can find the appropriate update here:
http://www.adobe.com/support/downloads/product.jsp?product=10&platform=Windows,/A>.

Adobe Reader users on UNIX can find the appropriate update here:
http://www.adobe.com/products/reader/unix9/ (download latest update from 9.3.1 folder).