That sounds like a logic flaw because iPhones and most other devices like it will normally auto update after a short while. I think more people will rely on that feature than browse, uh, bugs.chromium.org...

This view of it will assist hackers in getting a head start before the auto update cycle gets to your device and you're notified. And if you're hit but something like this before that, your iPhone will no longer be able to update and apply the fix.

Of course, there's no way to find an objectively "correct" time frame since update cycles vary, but a month or two ought to give plenty of time for the updates to roll out and users to be made aware.