This indicates an attack attempt against a Memory Corruption vulnerability in Photoshop CC.
The vulnerability is due to an error when the vulnerable software handles a maliciously crafted PCT file. A remote attacker may be able to exploit this to execute arbitrary code within the context of the application, via a crafted PCT file.
Photoshop CC 2018 19.1.5 and earlier
Photoshop CC 2017 18.1.5 and earlier
System Compromise: Remote attackers can gain control of vulnerable systems.
Apply the most recent upgrade or patch from the vendor.