Sayyiduna Abdullah bin Sufyan (may Allah be pleased with him) narrates: The Prophet (peace and blessings be upon him) had himself cupped while fasting.
Al-Tabarani recorded it in al-Mu'jam al-Kabir, and its chain contains a narrator, Muhammad bin Abi Layla, who has been criticised.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الصيام / 5001