No, China can't just Gitmo an American journalist on American soil.

But now China can send some legal pornography (eg closeup pussy pictures), disturbed to match a CSAM hit, to a journalist they don't like and get them in jail.

Why can't China do this before? Because previously, they'd still need to tip off authorities, which has an attribution trail and credibility barrier. Now, they can just use Pegasus to plant these images and then watch as Apple turns them into the Feds. Zero links to the attacker.

The scenario you describe has already been extant for the past ten years. Unreported zerodays could have been used at any time to inject a CSAM hit into someone's camera roll, way back in time where they wouldn't see it, in order to get them investigated. Their phone would have uploaded it to iCloud or Google Photos or Dropbox Whatever and the CSAM detections at each place would have fired off. No need for any of this fancy AI static nonsense.

I know of zero instances of this attack being executed on anyone, so apparently even though it's been possible for years, it isn't a material threat to any Apple customers today. If you have information to the contrary, please present it.

What new attacks are possible upon device owners when the CSAM scanning of iCloud uploads is shifted to the device, that were not already a viable attack at any time in the past decade?