No one alive can stand against this duo!
I'm being completely serious.
I really, truly am.
Kabuto is a sneaky son of a *****. He has, either personally or through extraordinary contacts in what used to be Orochimaru's network, managed to collect genetic material from THE most powerful people who lived since the villages were founded (with the possible exception of Jiraiya and Sakumo).
What does Hidan need to perform his curse?
Blood. If Kabuto can gather DNA from MADARA UCHIHA, (who he should have no idea lived beyond the Valley of the End) it shouldn't be hard from him to collect blood from whoever he wants among the living. It's not like people aren't bleeding all over the place.
And Hidan can cause ANYONE lethal injuries, without regard for protection, without regard for distance (as far as we know). If Madara himself had surrounded the Juubi with Perfect Susanoo, and Hidan already had his ritual ready, Madara would lose. Hidan would be vaporized afterwards by the Juubi, but Madara WOULD die. And if Hidan can perform his ritual outside of the target's line of sight or (if it's possible, and I don't see why it shouldn't be) from a couple of kilometers away, there would be no possible retaliation. And we don't KNOW that the ritual wouldn't work on the other side of the Elemental countries.
Tl;dr: If Hidan could use his curse like an actual ninja, and had access to Kabuto's stores of DNA, NO-ONE would be safe.
Edit: Oh it got moved to Versus. That's nice. I HAD hoped for intelligent debate on the impossible mechanics of Hidan's abilities and Kabuto's insane sneakiness, but I suppose endless repetitions of "Madara low diff" and "Obito solo's" is just as good.