Ata' bin al-Sa'ib (may Allah have mercy on him) said: A group of the people of Basrah - among them al-Hasan (al-Basri) - testified before me concerning Sayyiduna Ma'qil bin Yasar (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) came upon a man who was being cupped while he was fasting, and he (peace and blessings be upon him) said: "The one who cups and the one who is cupped have both broken their fast."
Hadith Referenceالمعجم الكبير للطبراني / باب الميم / 17617