A critical vulnerability has been identified in Adobe Reader 9 and Acrobat 9 and earlier versions. This vulnerability would cause the application to crash and could potentially allow an attacker to take control of the affected system. This issue is remotely exploitable and there are reports that this issue is being exploited.
Adobe recommends users of Adobe Reader and Acrobat 9 update to Adobe Reader 9.1 and Acrobat 9.1. Adobe is planning to make available updates for Adobe Reader 7 and 8, and Acrobat 7 and 8, by March 18. In addition, Adobe plans to make available Adobe Reader 9.1 for Unix by March 25.
Adobe recommends Adobe Reader users update to Adobe Reader 9.1 available here.