Sahih Muslim 1905
صحيح مسلم#1905SahihUbayy b. Ka'b reported that he was sitting in a mosque that a person entered it and he observed prayer, and made recitation, the rest of the hadith is the same
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: 6:333