It's nowhere close to the greatest security failure in a decade. It's not even a contender in the far off distance. It's a well publicized vulnerability, and it's quite silly, but in the scheme of things it's just a Tuesday for CVE writers. We even had a vulnerability functionally identical to this, and similar in both severity and silliness, hit Linux within the past year.

If you're talking about Apple specifically, it's still not that bad. The vulnerability couldn't be arbitrarily executed remotely with default OS settings, and it didn't grant kernel access. The Trident flaws were significantly worse than this, and that's just the first that comes to mind.

Yes, yes, I know this wasn't the thrust of your point...but still. People get kind of hyperbolic when it comes to rating security vulnerabilities. It's more silly than it is severe. I expect at least one vulnerability of comparable impact on every major point release of every major operating system and web browser (not that this is a good thing, but it's logistically realistic). I don't think this is particularly bad for Apple's public image or reputation. Headlines about "the sky is falling!" vulnerabilities make the rounds every so often; for better or worse, it never really seems to stick in public consciousness.