"We were with Umm Salamah and we were discussing Mahdi. She said: 'I heard the Messenger of Allah (ﷺ) say: "Mahdi will be one of the descendents of Fatimah."
Sunan Ibn Majah Book 36, Hadith 161
← Previous Hadith "Mahdi is one of us, the people of the Household. Allah will rectify him in a single night."

Sunan Ibn Majah Book 36, Hadith 160 Next Hadith → "I heard the Messenger of Allah (ﷺ) say: 'We, the sons of 'Abdul-Muttalib, will be leaders of the people of Paradise: Myself, Hamzah. 'Ali, Ja'far, Hasan, Husain and Mahdi."

Sunan Ibn Majah Book 36, Hadith 162