Sahih al-Bukhari 889
صحيح البخاري#889SahihNarrated Hudhaifa:When the Prophet (ﷺ) got up at night (for the night prayer), he used to clean his mouth
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 11:14