While there is a history and a lot of debate on both sides of the argument, there is one key basis for the concept of "sola scriptura." That the written documents which make up the 66 book Bible are regarded as the word from God. Now God is inerrant. So unless one is asserting other sources which are the word of God, then Sola Scriptura stands.
Here it is, those who deny Sola Scriptura are claiming other special revelation from God regading Jesus of Nazareth being the Lord and Christ.
Fact, all professing Christians make some kind of claims regarding the 66 book Bible. Every professing Christian group makes some kind of appeal to those (66) written Scriptures for their authority. There are no exceptions.
Jhn 1:1¶
In the beginning was the Word, and the Word was with God, and the Word was God.
Of the Godhead Jesus has taken sole action regarding the sinners, He created the place , was the communication, both OLD at New Testament and became us to die. There is be no other communication from God for Salvation.
Jhn 1:14
And the Word was made flesh, and dwelt among us, (and we beheld his glory, the glory as of the only begotten of the Father,) full of grace and truth.
When He left, the Holy Spirit leads us to Him, Jesus, no revelation is necessary . The Holy Spirit only leads us to Christ .
God did communicate to non Hebrew people throughout History for different purposes but Salvation is through the Jews.
So if another claims the right of inspiration, they lie. If they claim God led them to understand Scripture, it is correct.