Sahih Muslim 2594
صحيح مسلم#2594SahihSulaiman b. Yasar reported that he asked Umm Salama whether a person (who gets up) in the morning in a state of junub should observe fast. She said:The Messenger of Allah (ﷺ) (at times) got up in the morning in a state of junub, not because of sexual dreams (but on account of intercourse at night), and then observed fast
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih Muslim is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 13:100