Copilot will prompt you before accessing untrusted URLs. It seems a crux of the vulnerability that the user didn't need to consent before hitting a url that was effectively an open redirect.
Does it do that using its own web fetch tool or is it smart enough to spot if it's about to run `curl` or `wget` or `python -c "import urllib.request; print(urllib.request.urlopen('https://www.example.com/').read())"`?
What are "untrusted URLs" ? Or, more to the point: What are trusted URLs?
Prompt injection is just text, right? So if you can input some text and get a site to serve it it you win. There's got to be million of places where someone could do this, including under *.google.com. This seems like a whack-a-mole they are doomed to lose.