Sahih al-Bukhari 1811
صحيح البخاري#1811SahihNarrated Al-Miswar:Allah's Messenger (ﷺ) slaughtered (the Hadi) before he had his head shaved and then he ordered his Companions to do the same
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: 27:6