Since the Catechism, CCC section 1033 to 1037, teaches us that hell indeed exists, and our ending up there is a real possibility, this would exclude a certainty of universal salvation. The best that we Catholics can officially have is a “hopeful universalism.”
CCC 1037 states: God predestines no one to go to hell, for this, a willful turning away from God (a mortal sin) is necessary, and persistence in it until the end. In the Eucharistic liturgy and in the daily prayers of her faithful, the Church implores the mercy of God, who does not want “any to perish, but all to come to repentance.”
Church Fathers and theologians, most notably Hans Urs von Balthasar, have rightly pointed out that the Church has never declared that any particular individual is in hell, and so the faithful can, and even should, maintain the hope that no person is in hell. Philosophers and saints, such as Edith Stein, St. Benedicta of the Cross, have surmised how God might accomplish this while respecting our free will.
Good books which I have read on this topic include A Catholic Reading Guide to Universalism, by Fr. Robert Wild, Salvation and Damnation, by Fr. William J. Dalton, S.J., and of course, Dare We Hope That All Men Be Saved? by von Balthasar.