This indicates an attempt to exploit a Memory Corruption vulnerability in Apple WebKit.
The vulnerability is due to an error when the vulnerable software attempts to handles maliciously crafted web page. An attacker may exploit this vulnerability by sending a specially crafted web page.
Apple iOS before 9.3.2
Safari before 9.1.1
tvOS before 9.2.1
System Compromise: Remote attackers can gain control of vulnerable systems.