Catholics are not free to dissent from the Church's official teaching, while it is not only lawful, but obligatory to reject the teaching of a catechism, which is not part of official Church teaching (i.e. the Magisterium), if it contradicts something of greater weight, such as a Council or encyclical.
However, the so-called Catechism of the Catholic Church was promulgated by Karol Wojtyla (also known as John Paul II) using the following words:
John Paul II, Fidei Depositum, Oct. 11, 1992: “JOHN PAUL, BISHOP, SERVANT OF THE SERVANTS OF GOD FOR EVERLASTING MEMORY, To my Venerable Brothers the Cardinals, Patriarchs, Archbishops, Bishops, Priests, Deacons, and to all the People of God…. The Catechism of the Catholic Church, which I approved June 25th last and the publication of which I today order by virtue of my Apostolic authority, is a statement of the Church’s faith and of Catholic doctrine… I declare it to be a sure norm for teaching the faith.
This statement meets the three criteria for infallibility as outlined by the Vatican Council:
...we teach and define as a divinely revealed dogma that when the Roman Pontiff speaks ex cathedra, that is, when, in the exercise of his office as shepherd and teacher of all Christians, in virtue of his supreme apostolic authority, he defines a doctrine concerning faith or morals to be held by the whole Church, he possesses, by the divine assistance promised to him in blessed Peter, that infallibility which the divine Redeemer willed his Church to enjoy in defining doctrine concerning faith or morals. Therefore, such definitions of the Roman Pontiff are of themselves, and not by the consent of the Church, irreformable.
It is also generally admitted by all that when the Roman Pontiff confirms an act of a Roman congregation in specific form, that is, he employs his apostolic authority and directs it towards the whole Church, that act is binding and infallible.
Clearly, John Paul II intended to bind the teachings of the CCC on the universal Church. If you accept him as a legitimate successor of St. Peter then you are bound to submit to his supreme authority. You are the ecclesia docta, the Pope is the ecclesia docens, it is his to teach and yours to suffer yourself to be taught.
This fact is problematic for those who recognize the numerous heresies in the Catechism but who insist on proclaiming that the man who kissed the Quran,
and actively partook in many pagan rituals,
is the Vicar of Christ.
To conclude, as a Catholic you are not free to dissent from official Church teaching, you may only conclude that since heresy can never be taught by the Church, those promulgating it cannot be the Church.
For more on the outrageous apostate who taught that man is God see here.
