Sahih al-Bukhari 3764
صحيح البخاري#3764Sahihحَدَّثَنَا الْحَسَنُ بْنُ بِشْرٍ، حَدَّثَنَا الْمُعَافَى، عَنْ عُثْمَانَ بْنِ الأَسْوَدِ، عَنِ ابْنِ أَبِي مُلَيْكَةَ، قَالَ أَوْتَرَ مُعَاوِيَةُ بَعْدَ الْعِشَاءِ بِرَكْعَةٍ وَعِنْدَهُ مَوْلًى لاِبْنِ عَبَّاسٍ، فَأَتَى ابْنَ عَبَّاسٍ فَقَالَ دَعْهُ، فَإِنَّهُ صَحِبَ رَسُولَ اللَّهِ صلى الله عليه وسلم.
Narrated Ibn Abu Mulaika:Muawiya offered one rak`a witr prayer after the `Isha prayer, and at that time a freed slave of Ibn `Abbas was present. He (i.e. the slave) went to Ibn `Abbas (and told him that Muawiya offered one rak`a witr prayer). Ibn `Abbas said, "Leave him, for he was in the company of Allah's Messenger (ﷺ)
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: 62:109