That's the tricky part; I can't disable UPnP, as many others can't (which is why this is just a workaround, and not a fix as many people state).
For how my ISP uses the mechanism behind NAT, if I disable UPnP I'm practically disabling my Internet connection and anything related to it.
I can just hope to get lucky and play, right now... Well, besides being happy others don't have this issue, as the game would likely die otherwise.
It's not a big deal tho, I've got plenty of stuff to do other than playing CoD, and I can always try going back to BO2 if things start going south