This issue was addressed with improved checks. This issue is fixed in iOS 12.4, macOS Mojave 10.14.6, tvOS 12.4, watchOS 5.3. An attacker may be able to trigger a use-after-free in an application deserializing an untrusted NSDictionary.
https://support.apple.com/HT210353
https://support.apple.com/HT210351