This indicates an attack attempt to exploit a Memory Corruption vulnerability in Windows PDF Library.
The vulnerability is due to an error when the vulnerable software handles a maliciously crafted PDF file. A remote attacker may be able to exploit this to gain access to process address space, leading to possibly further attacks.
Windows Server 2012
Windows Server 2012 R2
Windows RT 8.1
Information Disclosure: Remote attackers can gain sensitive information from vulnerable systems.
Apply the most recent upgrade or patch from the vendor.