I was with the Prophet ﷺ in Medina, and that was on the eighteenth night of Ramadan. He saw a man being cupped, and the Messenger of Allah ﷺ said, "The one who performs cupping and the one upon whom it is performed have both broken their fast."
حدثنا محمد بن يزيد حدثنا أبو العلاء يعني القصاب عن قتادة عن أبي قلابة عن أبي الأشعث عن أبي أسماء
كنت مع النبي ﷺ بالمدينة قال وذاك لثمان عشرة خلون من رمضان فأبصر رجلا يحتجم فقال رسول الله ﷺ أفطر الحاجم والمحجوم
Its isnad is sahih. Abu Ala al-Qassab is Ayub bin Abu Miskeen al-Tamimi al-Wasiti. Ahmad deemed him trustworthy, despite some error in his narrations, and Muslim and Nasai also deemed him trustworthy. Daraqutni and Ibn Adi said, "There is no harm in him."