The Book of Marriage
26/37. Chapter:
The Concession Allowing A Muhrim To Marry
Sunan an-Nasai
أَخْبَرَنَا مُحَمَّدُ بْنُ مَنْصُورٍ، قَالَ حَدَّثَنَا سُفْيَانُ، عَنْ عَمْرٍو، عَنْ أَبِي الشَّعْثَاءِ، أَنَّ ابْنَ عَبَّاسٍ، أَخْبَرَهُ أَنَّ النَّبِيَّ صلى الله عليه وسلم تَزَوَّجَ مَيْمُونَةَ وَهُوَ مُحْرِمٌ .
It was narrated from Abu Ash-Sha'tha' that Ibn 'Abbas told him: "The Prophet married Maimunah when he was a Muhrim."
Reference : Sunan an-Nasa'i 3272In-book reference : Book 26, Hadith 77English translation : Vol. 4, Book 26, Hadith 3274