It's only been said that they have conquered many worlds, and continue to do so but it had not been described what wars they're fighting beyond this one.
English
-
Then it's pure speculation and assumptions
-
No it is Canon, we just don't know what their wars are like.
-
Noooo it's speculation and assumptions. We know, yes, that they are supposedly involved in multiple wars across a vast empire but we have no actual proof of this. Sure it is canon but it is still speculation towards the extent of the wars they are involved with. For some reason I doubt it surpasses what they are going through with the Vex, especially since they have considerable intel on them, as do The Fallen.
-
"I think you could follow a trail of shattered worlds all the way to their home." Tactically efficient, disciplined, and unrelenting, the Cabal are the greatest known military force in the system. Their origins and ultimate objectives are a mystery, but it seems clear they have conquered more worlds than humanity has ever known. - See more at: http://destiny-grimoire.info/#Collection-Cabal
-
'I think' 'It seems' Speculation. Just because they have a big army and are from outside the system doesn't show much, especially when they have barely done any advances in system and seemingly have, for no reason, not attempted to destroy one city. We hear a lot of great things and we see big things built but it doesn't go further than that.
-
It means that they're not using anywhere near their full military capacity. so it's logical to assume there other wars, and not just sitting around doing nothing.