Here's the problem.
1) Scripture is inerrant. That is, on points of faith and morals, it does not contain error. Sure, it may not accurately describe things in a way that is in accordance with experimental science, but Scripture is not meant to be a science textbook, It is, in various books and passages, a history. It engages in poetry, allitration, hyperbole, sarcasm, even cynicism, but it is on matters of faith and morals without error.
2) Scripture says Judas repented (Matthew 27:3). Notice: although all Christians agree Peter repented, it says nowhere explicitly in Scripture that Peter did, in fact, repent. Luke's Gospel tells us Peter "wept bitterly" (Luke 22:62), but it does not explicitly say he repented. Peter's repentance is implied, never explicit. The explicit words of Scripture tell us of Judas' repentance.
So... that's an issue.
Now, one might argue that is is clearly not an issue because the Church tells us that Judas is in hell for having betrayed Christ. But the Church doesn't actually say that anywhere in any of her official documents. Sure, individual saints, Fathers of the Church, Doctors of the Church either implicitly or explicitly tell us Judas is in hell, but those same individuals are often unclear on points of doctrine or get specific doctrinal points wrong, despite their sanctity. The Church exists to correct those errors and steer us on the clear path. The Church's Magisterial authority does not clearly state Judas is definitely in hell. (see note below)
Now, perhaps this is all just a translation problem. If we look at the Greek, we can see that Judas "metamelloma" (repented). Does "metamelloma" mean "equivocal" or "incomplete" or does it have some other kind of asterick?
According to James Glentworth Butler, "as nearly as possible [metamelomai] is the exact equivalent of the word Repent or Repentance." Worse, God chastises those who did not "metamellomai" after hearing John. (Mat 21:32). But Judas DID metamellomai. So... why is metamellomai sufficient when people listen to John, but not sufficient for Judas? It's the same word.
If there is some kind of asterick surrounding "metamelloma", then why are the tax collectors and prostitutes who do this after hearing John's message forgiven? Or, conversely, if the "metamelloma" of the prostitutes is sufficient, then why isn't Judas' "metamelloma" sufficient?
What options are available here?
1) Well, we could conclude that Scripture is wrong, Judas' repentance wasn't real, and Judas is going to hell for betraying Christ. But if Scripture is wrong on this point, that means Scripture is not inerrant. That's a non-starter.
2) We could conclude that Scripture is correct, Judas did, indeed, engage in true repentance just like the tax collectors and prostitutes. So, is Judas in hell? If he is, then he isn't in hell for betraying Jesus, because Judas repented of that. He would have to be in hell for some other reason. Perhaps his suicide?
But there's a second problem. Scripture describes him as dying in two different ways.
Matthew 27:5: Then he threw down the pieces of silver in the temple and departed, and went and hanged himself.
Acts 1:18: Now this man purchased a field with the wages of iniquity; and falling headlong he burst open in the middle and all his entrails gushed out.
There have been various attempts to harmonize these two discordant passages. The most popular is to say that he did, indeed, hang himself, but he hung himself in a tree in the Field of Blood. After he was dead, either the rope broke and his bloated corpse fell to the ground and burst open, or the simple act of bloating was sufficient to cause his entrails to burst out and his corpse fell in some unspecified manner.
This is vaguely disorienting. Perhaps some variation on those themes work, although it isn't entirely clear why the two passages appear to disagree so strongly. You would think Matthew and Luke (the author of Acts) would have talked with each other about Judas' situation, or that Peter would have been better informed about the fate of one of the Twelve. But, leave that as it may be. What do we do with the money?
Notice that in Matthew 27:5, Judas throws down and abandons the pieces of silver. The chief priests then pick up the money and buy the field that became known as the Field of Blood. In Acts 1:18, Peter says Judas didn't throw the money away, instead, Peter says Judas kept the money and bought a field with it. Which one is it?
Matthew 27: 5-8: And casting down the pieces of silver in the temple, he departed: and went and hanged himself with an halter. 6But the chief priests having taken the pieces of silver, said: It is not lawful to put them into the Temple treasury, because it is the price of blood. 7And after they had consulted together, they bought with them the potter's field, to be a burying place for strangers. 8For this cause the field was called Haceldama, that is, The field of blood, even to this day.
Acts:1:18-19: And he indeed hath possessed a field of the reward of iniquity, falling headlong burst asunder in the midst: and all his bowels gushed out. 19And it became known to all the inhabitants of Jerusalem: so that the same field was called in their tongue, Haceldama, that is to say, The field of blood.
To make matters worse, it is Peter who tells us the Acts 1 story, so the discordance between Matthew 25 and Acts 1 involves not just Scripture's inerrancy, but Peter's infallibility. Not only do we have the question of (1) Judas repentance, we also have the questions of (2) who, exactly, bought the field and (3) why, exactly, was it called the Field of Blood?
Now, the third question is easily harmonized. A group might have more than one reason to name a thing, and it is quite possible that both the method of purchase and the bursting of bowels combined to give the field its name. But the purchase itself... how do you harmonize that? The only possible way to make it work is to say the chief priests made the purchase, but since they made that purchase with money they morally refused to accept, they made it with Judas' money, properly speaking, and so it was Judas' purchase, even though Judas had not himself made the purchase. But if we insist that the chief priest's implicitly repudiated the money, so it was really Judas' money, then we have to ignore the fact that Scripture explicitly says Judas also repudiated the money. Why do the chief priests get to repudiate the money but Judas doesn't get to?
We're back to the same problem. Scripture explicitly says Judas repented. Scripture explicitly says Judas repudiated the money. Scripture only implies Peter repented, Scripture only implies the chief priests repudiated the money (after all, they used the money, so it's not entirely clear that they really did repudiate it). We're more than happy to grant the implicit motivations, and very quick to reject the explicit Scriptural statements about Judas.
Keep in mind also that both passages agree on the name of the field. It is not called "Field of the Damned." It is called "Field of Blood." From a Scriptural perspective, this is very noteworthy. According to Scripture, blood is life.
Only you shall not eat flesh with its life, that is, its blood. (Gen 9:4)
For the life of the flesh is in the blood (Lev 17:11)
Only be sure not to eat the blood, for the blood is the life, and you shall not eat the life with the flesh. You shall not eat it; you shall pour it out on the ground like water. (Deuteronomy 12:23)
From the perspective of Scriptural concordance and interpretation, given that blood is equated to life, the name of the field could as easily be translated either "Field of Blood" or "Field of Life." Does this mean Judas' blood is life-giving? Not at all. We just need to remember that for the Scripturally knowledgeable and Scripturally observant Jew, the word "blood" has entirely different connotations than it does for 21st century Christians. Blood was holy, the blood of animal sacrifices at Passover was used to anoint the altar. Judas' blood was poured into the ground when he "burst asunder" (or the money that bought the shedding of Christ's blood was poured into the purchase, or both) to such a degree that the field was named after blood. The one thing the two passages do agree on: the money given Judas to betray Christ, one way or another, was used to purchase that field. The price of Christ's blood and the actual life-blood of Judas are co-mingled in that Field of Blood.
If Christ is the scapegoat for our sins, then Judas' role in salvation history may be seen in another light. In Leviticus 16, two goats are given to the priests for sacrifice. One is killed, the other is assigned to have the sins of the nation put on its head and be released, it is the Escape Goat (scapegoat). The priest who lays hands on the Escape Goat and sends it out into the wilderness is, by that action, rendered unclean. He cannot return to the people of Israel until he has ritually bathed. The Jewish ritual bath (mikveh) that the Old Testament priest must undergo is a precursor to the baptism instituted by Christ.
In the Garden, Judas' kiss sends Jesus into the wilderness of the secular world and secular judgement.
Since Jesus is the Escape Goat, this makes Judas the impure Old Testament priest who requires a ritual bath in order to return to God's people. But there is no record of Judas going through any Old Testament purification ritual or either of the New Testament purification sacraments (baptism and confession) that would restore his purity. Of course, Scripture does not explicitly describe any of the tax collectors and prostitutes who heard John as having undergone these rituals either. But, it is an interesting thing to think about.
Scripture never explicitly tells us why Judas committed suicide. While the Church has historically dealt harshly with suicides, for example, refusing them for centuries the right to be buried in holy ground, medical advances have made it clear that some cases of suicide are deeply influenced by uncontrollable medical conditions. As a result, the Church has greatly mellowed in her treatment of suicides.
If we accept the inerrancy of Scripture, than we must accept that Judas did, indeed, experience true repentance. We must also accept that he did, indeed, truly repudiate the payment for his betrayal of Christ. It is true that he is not known to have undertaken any ritual attempt to regain purity of life. However, given the Scriptural facts of his repentance, combined with the increased medical understanding of suicide, an understanding not possessed by the Fathers and Doctors of the Church, can Catholics in the 21st century accept that "Judas in hell" may possibly be incorrect? If the names of the twelve Apostles are written on the twelve courses of the foundation of the Heavenly City, does that mean Judas' name is written on the foundation of heaven?
The simple answer: Yes. Just as many of the Fathers and Doctors were wrong about the Immaculate Conception, so many of them may have been wrong about Judas being in hell.
NOTE
The Catholic Church cannot definitively say anyone is in hell because it is not part of her mission to do so. The Church shares Christ's mission. The Son of God became man so that all men might be saved. If the Church were to declare that someone was in hell, then that declaration alone would be sufficient for damnation. But Christ did not come into the world to damn men to hell, He came to save men for heaven. Thus, the Church can categorically state that specific people are in heaven (the canonized saints, the angels) because that is Christ's mission, but declaring someone to be in hell is not part of Christ's mission and so not a statement the Church can officially make about any particular person.
The Church clearly states that persons are in hell. We know that persons are in hell. Angelic persons are in hell. Fallen angelic persons are demons, those persons are in hell. But the Church cannot say any particular human person is in hell.
The same issue applies to private apparitions. First, if we follow the advice of Doctor of the Church, St. John of the Cross, we should ignore ALL private apparition. If we decide we will not follow the spiritual advice of a Doctor of the Church, then we must at least realize that visionaries can get messages wrong or misunderstand them. Yes, even Fatima visionaries can get things wrong.