What data can apps access without your explicit permission?

install tiktok (if you do not have it) and disable everything, no mic/camera/photos/contacts/… nothing. then ask you partner/friend/… to send you some text messages about purchasing an ebike for instance. open safari and do some searches for ebikes (https://blue.bike perhaps and others)… the head on over to tiktok and scroll a bit and see if any ebikes start showing up…

a) There is no evidence that Apple is sharing messages with third parties.

b) You are simply confirming my point which is that when you visit a website it is able to tie you to an consistent identifier through the APIs your browser supports.

there is no evidence for a whole lot of things… /s

You do realize that it was the “open safari and do some searches for ebikes” step that causes you to get the ads in TikTok, right?

So you think there a conspiracy and that TikTok for iOS has been able to break out of its sandbox and read your text messages?

This would have made news if so.

What? No. Apps are guaranteed to be sandboxed and can’t access anything you don’t let them.