This indicates an attack attempt to exploit a Memory Corruption vulnerability in Adobe Reader and Acrobat.
The vulnerability is due to an error when the vulnerable software handles a maliciously crafted EMF file. A remote attacker may be able to exploit this to execute arbitrary code within the context of the application, via a crafted EMF file.
Adobe Systems Acrobat 2017 2017.008.30051 and earlier versions
Adobe Systems Acrobat DC (Classic) 2015.006.30306 and earlier versions
Adobe Systems Acrobat DC (Continuous) 2017.009.20058 and earlier versions
Adobe Systems Acrobat XI 11.0.20 and earlier versions
System Compromise: Remote attackers can gain control of vulnerable systems.
Apply the most recent upgrade or patch from the vendor.