An out-of-bounds read was addressed with improved input validation. This issue is fixed in iOS 12.1.3, macOS Mojave 10.14.3. An attacker in a privileged network position may be able to execute arbitrary code.
CWE-125 - Out-of-Bounds Read
Out-of-bounds read is a vulnerability that allows access to memory beyond the authorized accessible location. Such a vulnerability compromises the confidentiality of the trusted environment in the application and enables an attacker to launch further attacks by leveraging the exposed information.