This last pope was considered Jewish from his mothers side. At least that is what I've come across. Not a practicing Jewish pope, however, but that is what I have read.
Not that there is anything wrong with that.
I never heard of any connection between Judaism and the mother of Pope John Paul II. His "earthly Mother" was from Lithuania and was a very devout Catholic. Fr. Malachy Martin's book, "The Keys To This Blood" had quite a bit about JPII's life and I do not recall anything said about the mother being Jewish. I think I have the name of the book correct. I read it a long time ago.
On the other hand, JPII's heavenly mother was the Blessed Virgin Mary. Now, she really does have a Jewish connection!