This indicates an attack attempt to exploit a Memory Corruption vulnerability in Microsoft Edge.
The vulnerability is due to an error when the vulnerable software attempts to handles maliciously crafted PDF file. An attacker can exploit this by tricking a user into opening a maliciously crafted PDF file and execute arbitrary code within the context of the application.
Microsoft Edge Windows 10 for 32-bit Systems
Microsoft Edge Windows 10 for x64-based Systems
Microsoft Edge Windows 10 Version 1511 for 32-bit Systems
Microsoft Edge Windows 10 Version 1511 for x64-based Systems
System Compromise: Remote attackers can gain control of vulnerable systems.
Apply the most recent upgrade or patch from the vendor