The Catechism of the Catholic Church is a presentation of Church doctrine that has previously been taught with varying degrees of authority. To determine the degree of authority with which any given doctrine has been taught, one must investigate the history of that particular teaching. Look to the Catechism’s footnotes for help in this regard. There you will find references to Church councils, documents, canon law, Scripture, etc., all of varying degrees of authority.
Whatever the underlying degree of authority any given doctrine may carry, Pope John Paul II called the Catechism "a statement of the Church’s faith and of Catholic doctrine, attested to or illumined by Sacred Scripture, the apostolic Tradition, and the Church’s magisterium" (Fidei Depositum 3). He declared it to be "a sure norm for teaching the faith."