Sahih al-Bukhari 193
صحيح البخاري#193SahihNarrated 'Abdullah bin 'Umar:"During the lifetime of Allah's Messenger (ﷺ) men and women used to perform ablution together
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: 4:59