This indicates an attack attempt to exploit a Memory Corruption vulnerability in WebKit, a component of Apple Safari.
The vulnerability is due to an error when the vulnerable software handles column blocks and buttons in a certain way. An attacker can exploit this by tricking an unsuspecting user into visiting a malicious webpage and execute arbitrary code within the context of the application.
Apple iOS prior to 12.1.1
Apple tvOS prior to 12.1.1
Apple watchOS prior to 5.1.2
Apple Safari prior to 12.0.2
Apple iTunes prior to 12.9.2 for Windows
Apple iCloud prior to 7.9 for Windows
System Compromise: Remote attackers can gain control of vulnerable systems.
Apply the most recent upgrade or patch from the vendor.