Sahih al-Bukhari 1140
صحيح البخاري#1140Sahihحَدَّثَنَا عُبَيْدُ اللَّهِ بْنُ مُوسَى، قَالَ أَخْبَرَنَا حَنْظَلَةُ، عَنِ الْقَاسِمِ بْنِ مُحَمَّدٍ، عَنْ عَائِشَةَ ـ رضى الله عنها ـ قَالَتْ كَانَ النَّبِيُّ صلى الله عليه وسلم يُصَلِّي مِنَ اللَّيْلِ ثَلاَثَ عَشْرَةَ رَكْعَةً مِنْهَا الْوِتْرُ وَرَكْعَتَا الْفَجْرِ.
Narrated `Aisha:The Prophet (ﷺ) used to offer thirteen rak`at of the night prayer and that included the witr and two rak`at (Sunna) of the Fajr prayer
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
Every narration in Sahih al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 19:21