Mishkat al-Masabih #1921

Shaddad b. Aus said that when God’s messenger was walking hand in hand with him on the eighteenth of Ramadan he came across a man in al-Baqi who was being cupped and said, “The one who cups and the one who is cupped have broken their fast.” Abu Dawud, Ibn Majah and Darimi transmitted it. The shaikh and imam Muhyi as-sunna said that some of those who allow cupping have interpreted it as meaning that they exposed themselves to the danger of breaking the fast, the one who was cupped on account of weakness, and the one who did the cupping because he could not guarantee that something would not get into his stomach by sucking the flask.