Sahih al-Bukhari 6310
صحيح البخاري#6310SahihNarrated Aisha:The Prophet (ﷺ) used to pray eleven rak`at in the late part of the night, and when dawn appeared, he would offer two rak`at and then lie on his right side till the Muadhdhin came to inform him (that the morning prayer was due)
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: 80:7