[solarkraft]

First part: Not at all. Apps can‘t deeply integrate into the system and it’s always through very tightly defined APIs.

Second part: Technically yes, practically no. Apps are still tightly bound by the system.

Theoretically there can be exploits out of the app sandbox that could be caught before an app is released on the app store. But once the vulnerability it will quickly be closed - and while it‘s not known it also won’t be caught by the app store‘s automatic checks anyway, so it could also be inside of app store released apps.