Sahih Muslim 3453
The Book of Marriage
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 .
Yazid b. al-Asamm reported:Maimuna daughter of al-Harith narrated to me that Allah's Messenger (ﷺ) 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)
Text from the public-domain hadith-api dataset. Numbering follows that dataset and can differ by a few from some printed editions — check the wording, not only the number.