"No Catholic could subscribe even to moderate socialism." (Pope St. John XXIII)
CCC 2425: The Church has rejected the totalitarian and atheistic ideologies associated in modem times with "communism" or "socialism." ...
What popes have said about socialism: https://tfpstudentaction.org/blog/what-the-popes-really-say-about-socialism
RCsocial.net — a friendly social networking space for those with an interest in Catholicism.