Sahih al-Bukhari 778
صحيح البخاري#778SahihNarrated `Abdullah bin Abi Qatada:My father said, "The Prophet (ﷺ) used to recite Al-Fatiha along with another Sura in the first two rak`at of the Zuhr and `Asr prayers. A verse or so was audible at times and he used to prolong the first rak`a
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: 10:173