question #3 Sahih Muslim Introduction 62, Introduction, Narration 61 : What are the consequences of falsely attributing a hadith to a source?

‘I did not see Ayyūb speaking ill of anyone, ever, except for Abd al-Karīm- meaning Abū Umayyah’. So he mentioned him and said, may Allah have mercy on him ‘He is not trustworthy- he had asked me about a Ḥadīth of Ikrimah then said ‘I heard from Ikrimah’ [when relating the Ḥadīth].’