This indicates an attack attempt to exploit a Memory Corruption vulnerability in Adobe PDF Reader Browser Control.
Adobe Reader XI (11.0.06) and prior 11.x versions for Windows and Macintosh
Adobe Reader X (10.1.9) and prior 10.x versions for Windows and Macintosh
Adobe Acrobat XI (11.0.06) and prior 11.x versions for Windows and Macintosh
Adobe Acrobat X (10.1.9) and prior 10.x versions for Windows and Macintosh
System Compromise: Remote attackers can gain control of vulnerable systems.
Apply the most recent upgrade or patch from the vendor.