I don't use rails but it seems that the quality of releases have been going downhill over the pass months.
These are not new vulnerabilities, but are being discovered now, which means more spotlights are shining on the project. That's a sign of maturity too. From a maintenance standpoint, it will be a pain to apply patches to older software and those seeing heavy use, but it will cause some reexamination of existing code and practices.
There will be a domino effect of more eyes focusing on the code now, which in turn will lead to more discoveries of course, but hopefully, new fixes too.
The spate of recent vulnerabilities has more to do with YAML in particular than with rails itself.
I suggest that you follow the advice, "if you can't think of anything nice or constructive to say, bite your tongue". The irony is not lost on me that in taking you to task for the tone you couch your comments in I am failing to live up to my own advice, but I'll make an exception here.
The thought even crossed my mind while carefully drafting the above comment that I ought to preempt the accusation that I was committing this logical fallacy but I decided not to and now I wish the opposite.
Anyway, I hope you see the difference?
So it's basically a training system to encourage people to comment like this (remember; you need 500+ karma to down vote, so for many people, you can only ignore or up vote; therefore, all you see for a post is upvotes).
:/