Sahih al-Bukhari 288
صحيح البخاري#288SahihNarrated `Aisha:Whenever the Prophet (ﷺ) intended to sleep while he was Junub, he used to wash his private parts and perform ablution like that for the prayer
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: 5:40