This indicates an attack attempt to exploit a Memory Corruption vulnerability in Apple iOS WebKit.
The vulnerability is due to an error when the vulnerable software handles a maliciously crafted web page. An attacker can exploit this by tricking an unsuspecting user into visiting a malicious web page and execute arbitrary code within the context of the application.
Apple Apple TV version before 11.3
Apple Safari version before 11.1.1
Apple iPhone OS version before 11.4
Apple WatchOS version before 4.3.1
Apple icloud version before 7.5
Apple itunes version before 12.7.5
System Compromise: Remote attackers can gain control of vulnerable systems.
Apply the most recent upgrade or patch from the vendor.