´It was narrated that Sa'eed bin Musayyab said:` "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."
Hadith Referenceسنن ابن ماجه / كتاب الفتن / 4086
Hadith Gradingالألبانی:صحيح | زبیر علی زئی:إسناده حسن
Benefits and Issues: What has been recorded in Shia narrations regarding the Mahdi, whether true or false, is not correct. For example: his being hidden in the cave of Samarra, his possession of Dhu’l-Fiqar Haidari, his having the original Qur’an with him, and so on.
Source: Commentary on Sunan Ibn Mājah by Mawlānā ‘Atā’ullāh Sājid, Page: 4086