Is sharing "Fake News" and gossiping "Fake News" a mortal sin? (Catholic perspective)

In light of the current media trend of reporting and resorting to fake news and gossiping, and some netizens are somehow careless in becoming an instruments to spread it. Some social media users already have a habit of not making a diligent effort to verify the truthfulness of the news, and a lot of people who post on comments even link the fake news and worst posted it on their channels, clearly either unaware or intentionally to malign the character of a person. The subject of fake news usually is a recipient of character assassination and maligning one's dignity. The common habits in social media is sharing or posting "Fake News" and gossiping "Fake News" both action will end up damaging the subject's/person's character. **Has the Catholic Church particularly cited or considered sharing "Fake News" and gossiping "Fake News" as a griveous/mortal offense to God commandments especially if this common thing/actions in the mainstream & social media becomes habitual?**