Catechism of the Catholic Church §2511 — excerpt
"The sacramental seal is inviolable" (CIC, can. 983 # 1). Professional secrets must be kept. Confidences prejudicial to another are not to be divulged.
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.