By the time Wikileaks had it, it was probably out in the wild already.
Considering the incompetence we've seen in government, over and over and over and over again, is anyone ever still surprised by anything any government agency screws up? It wouldn't be difficult to believe that not only was it widely distributed already ‘in the wild’, but that it had actually been altered and reintroduced into CIA computers already.
Let’s not forget that these are the same folks who give surface to air missiles to jihadis.
It was probably sold on the black market within 24 hours of completion.