Catechism of the Catholic Church §1261 — excerpt
As regards children who have died without Baptism, the Church can only entrust them to the mercy of God, as she does in her funeral rites for them.
This translation is under copyright, so only the cited words are quoted here. Follow the link for the full text. Translation: English translation of the Catechism of the Catholic Church, 2nd ed. (Libreria Editrice Vaticana), as posted at vatican.va.
Whole chapters cited: Mark 10