There are tens of thousands of extremely skilled hackers selling exploits on the order of $10K to $100K. I'm fairly certain someone has been exploiting it. Not everyone is a good guy in the world.
Whether it has actually been used, given the value of the bug, is a different story. But it should absolutely be treated as "in active use" already, especially by state or state-sanctioned actors (like Hacking Team).
We do not have a 100% reliable way to determine whether an exploit is known by others (and likely never will have), and as such there is only one reasonable assumption left to make: assume that it is out in the wild and known by others.
This isn't a new concept - threat modelling requires that you assume every worst-case possibility is reality, so that you can guard against it. This was formalized in the 19th century as Kerckhoff's Principle[1], and undoubtedly existed before that in military circles. This applies equally to software security.
So given that we simply don't and can't know whether it is out in the wild, the most 'correct' assumption is that it is - because that lets us protect ourselves against that worst-case scenario, which may or may not be the case.
Are you refuting that fact, or are you not refuting that fact?