Mustadrak al-Hakim — Hadith 1583M2

Imam al-Hakim says: I heard Abu al-Hasan Ahmad bin Muhammad al-Anazi say: I heard Uthman bin Sa'id al-Darimi say: In my view the narration "The one who performs cupping and the one who has it done have broken their fast" is established as authentic because of the hadiths of Thawban and Shaddad bin Aws (may Allah be pleased with them both), and I hold this position. I also found Imam Ahmad bin Hanbal holding this position, and he used to mention that the hadith of Thawban and Shaddad was authentic in his view.