I feel like that's a threat that isn't super difficult to block. Unplug it from the internet, require it to go through an API intermediary to access web pages.
It could, but exposing that would doom the company entirely, and AI doesn't generate code with near the quality needed to get a model to mass adoption, insert malicious underhanded code, ensure that consistently looks innocuous enough to never be noticed, and- most importantly- actually exfiltrate data without being noticed. Once it is noticed, it's game over across the board.
[0] https://en.wikipedia.org/wiki/Underhanded_C_Contest