Judas wasn't an apostle, he was a disciple.
Judas was both a disciple (Greek: "mathētēs") and an apostle (Greek: "apostolos").
Matthew chapter 10
[
1] And when he had called unto him
his twelve disciples, he gave them power against unclean spirits, to cast them out, and to heal all manner of sickness and all manner of disease.
[
2] Now
the names of the twelve apostles are these; The first, Simon, who is called Peter, and Andrew his brother; James the son of Zebedee, and John his brother;
[
3] Philip, and Bartholomew; Thomas, and Matthew the publican; James the son of Alphaeus, and Lebbaeus, whose surname was Thaddaeus;
[
4] Simon the Canaanite,
and Judas Iscariot, who also betrayed him.
In fact, Matthias was chosen to replace Judas' apostleship.
Acts chapter 1
[
15] And in those days Peter stood up in the midst of the disciples, and said, (the number of names together were about an hundred and twenty,)
[
16] Men and brethren, this scripture must needs have been fulfilled, which the Holy Ghost by the mouth of David spake before
concerning Judas, which was guide to them that took Jesus.
[
17]
For he was numbered with us, and had obtained part of this ministry.
[
18] Now this man purchased a field with the reward of iniquity; and falling headlong, he burst asunder in the midst, and all his bowels gushed out.
[
19] And it was known unto all the dwellers at Jerusalem; insomuch as that field is called in their proper tongue, Aceldama, that is to say, The field of blood.
[
20] For it is written in the book of Psalms, Let his habitation be desolate, and let no man dwell therein: and his bishoprick let another take.
[
21] Wherefore of these men which have companied with us all the time that the Lord Jesus went in and out among us,
[
22] Beginning from the baptism of John, unto that same day that he was taken up from us, must one be ordained to be a witness with us of his resurrection.
[
23] And they appointed two, Joseph called Barsabas, who was surnamed Justus, and Matthias.
[
24] And they prayed, and said, Thou, Lord, which knowest the hearts of all men, shew whether of these two thou hast chosen,
[
25]
That he may take part of this ministry and apostleship, from which Judas by transgression fell, that he might go to his own place.
[
26] And they gave forth their lots;
and the lot fell upon Matthias; and he was numbered with the eleven apostles.
Just for the record.