As has been mentioned, the Church has never definitively said that Judas is in Hell, and it is of course possible that he repented before his death, but it isn’t looking good for him. Jesus is quoted as saying both at Matthew 26:24 and Mark 14:21 that if someone were to do such an act “it would have better for that one not to have been born.” Cornelius a Lapide on his commentary on this verse said “it is exceedingly probable that Judas abides in the deepest pit of Gehenna, near to Lucifer, and is there grievously tormented” for “true deicide”:
Matthew 26:24:
The Son of Man goes as it is written of him, but woe to that one by whom the Son of Man is betrayed! It would have been better for that one not to have been born.
From Cornelius a Lapide:
Ver. 24.
The Son of Man indeed goeth , &c.
Good were it for that man if he had not been born. For “far better is it not to exist at all, than to exist in evil. The punishment is foretold, that him whom shame had not conquered, the denunciation of punishment might correct,” says S. Jerome. He threatens him with the woe of damnation. For far better is it not to be, than to exist only to be endlessly miserable, as I have shown on Eccles. iv. 2, 3. Wisely does S. Jerome say (
Epist. ad Furiam ), “It is not their beginning which is inquired about in Christians, but their ending. Paul began badly but ended well. Judas’ beginning was commended, but his end was to be condemned as a traitor.”
Goeth. “By this word,” says Victor of Antioch, “Christ showeth that His death is like rather to a departure or passing away, than to real death. He signifies, likewise, by it that He went voluntarily to death.” Moreover, the betrayal of Judas was an act of infinite sacrilege, perpetrated directly against the very Person of Christ and God. Thus it was true
deicide. Wherefore it is exceedingly probable that Judas abides in the deepest pit of Gehenna, near to Lucifer, and is there grievously tormented. And this seems to be indicated by the word
woe , which Christ here pronounces upon him above the rest of the reprobates. Blessed Francis Borgia was wont, in meditation, in the depth of his humility, to place himself at the feet of Judas, that is to say, in the lowest pit of hell, exclaiming that there was no other place fit for him, neither in Heaven, nor in earth, nor under the earth, as the due reward of his sins.
http://www.catholicapologetics.info/scripture/newtestament/26matth.htm