This indicates an attack attempt to exploit a Memory Corruption vulnerability in Adobe Acrobat and Reader.
The vulnerability is due to a use-after-free error when the vulnerable software handles a maliciously crafted PDF file. A remote attacker can exploit this to exploit this to execute arbitrary code within the context of the application.
Adobe Reader X (10.1.2) and earlier 10.x versions for Windows and Macintosh
Adobe Reader 9.5 and earlier 9.x versions for Windows and Macintosh
Adobe Reader 9.4.6 and earlier 9.x versions for Linux
Adobe Acrobat X (10.1.2) and earlier 10.x versions for Windows and Macintosh
Adobe Acrobat 9.5 and earlier 9.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.