Yes, it might be possible for the terrorists to get hold of the nuclear weapons at some point in the future. This is because terrorist organizations such as ISIS are spreading over Syria and Iraq, and aim to take over the entire region cover Iran, Syra, and Iraq. If this happens, then the ISIS would certainly have control over the land which owns nuclear weapons. This could perhaps be a threat to the entire world.
Hence, ISIS should be stopped at all costs and be destroyed before that day comes. This might happen soon due to an increasing depletion of the ISIS’s resources.