It is narrated from Sayyiduna Abdullah al-Sunabihi (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Whoever begins the morning fasting and then has a wet dream, or has cupping done, or vomits involuntarily, does not have to make it up; and whoever vomits deliberately must make it up."
Imam al-Tabarani (may Allah have mercy on him) said: "No one other than Muhammad bin Aban (may Allah have mercy on him) narrated this hadith from Zayd bin Aslam (may Allah have mercy on him) from Sayyiduna al-Sunabihi (may Allah be pleased with him)."
Hadith Referenceالمعجم الأوسط / باب الألف / 1568
Hadith Gradingمحدثین:إسناده ضعيف لضعف أبي بلال الأشعري
Hadith Takhrij«قال الهيثمي: فيه أبو بلال الأشعري وهو ضعيف «مجمع الزوائد ومنبع الفوائد، ج 3، ص 171»»