Seems Russia made sure they never had full knowledge (i.e. launch codes etc).
They might have wished they had (esp. after the Maidan protests), but they didn't and signed a treaty back in 1994 already.
(pic: www.chathamhouse.org/media/comment/view/198641)
Nukes are a pretty tricky business, from what I know (testing, maintenance, development), apart from, of course, being highly regulated & watched.
Only state I am aware of that very likely has them (w/o admitting to it) is Israel.
Saudis financed the paki program, and could get it from them, but don't have them (nor the know-how).