Absolutely not acceptable
Honestly, there are no excuses for this. WTF, Apple? WT freaking F?
Microsoft has at least the decency to hide its problems and make it a bit of a challenge. I have never seen a decent company so dramatically drop the ball in quite some time. Even Microsoft Vista wasn't that exposed from a security angle.
Whoever was responsable for this cockup, firing is too good for them. At a minimum, this ought to involve tar & feathers.