Sahih Muslim , Book 16, Hadith 56 (In-Book) ⓘ
Yazid b. al-Asamm reported: Maimuna daughter of al-Harith narrated to me that Allah's Messenger married her and he was not in the state of Ihram. And she (Maimuna) was my mother's sister and that of Ibn 'Abbas (Allah be pleased with them).
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا يَحْيَى بْنُ آدَمَ، حَدَّثَنَا جَرِيرُ بْنُ حَازِمٍ، حَدَّثَنَا أَبُو فَزَارَةَ، عَنْ يَزِيدَ بْنِ الأَصَمِّ، حَدَّثَتْنِي مَيْمُونَةُ بِنْتُ الْحَارِثِ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم تَزَوَّجَهَا وَهُوَ حَلاَلٌ قَالَ وَكَانَتْ خَالَتِي وَخَالَةَ ابْنِ عَبَّاسٍ .
also referenced under: Hadith 1411 (Reference) & Book 8, Hadith 3285 (USC-MSA)