Sahih al-Bukhari 996
صحيح البخاري#996SahihNarrated `Aisha:Allah's Messenger (ﷺ) offered witr prayer at different nights at various hours extending (from the `Isha' prayer) up to the last hour of the night
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: 14:7