Adobe Reader and Acrobat 9.1.2 updates address critical security vulnerabilities and a number of customer workflow issues.
Adobe Reader and Acrobat 9.1.2 release notes

Adobe Reader 9.1.2 Update - Windows
Adobe Reader 9.1.2 Update - Macintosh
Adobe Acrobat 9.1.2 Professional and Standard Update - Windows
Adobe Acrobat 9.1.2 Professional Update - Macintosh