Sahih al-Bukhari 330
صحيح البخاري#330Sahihحَدَّثَنَا مُعَلَّى بْنُ أَسَدٍ، قَالَ حَدَّثَنَا وُهَيْبٌ، عَنْ عَبْدِ اللَّهِ بْنِ طَاوُسٍ، عَنْ أَبِيهِ، عَنِ ابْنِ عَبَّاسٍ، قَالَ رُخِّصَ لِلْحَائِضِ أَنْ تَنْفِرَ، إِذَا حَاضَتْ. وَكَانَ ابْنُ عُمَرَ يَقُولُ فِي أَوَّلِ أَمْرِهِ إِنَّهَا لاَ تَنْفِرُ. ثُمَّ سَمِعْتُهُ يَقُولُ تَنْفِرُ إِنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم رَخَّصَ لَهُنَّ.
Narrated Ibn `Abbas:A woman is allowed to leave (go back home) if she gets menses (after Tawaf-Al-Ifada). Ibn `Umar formerly used to say that she should not leave but later on I heard him saying, "She may leave, since Allah's Messenger (ﷺ) gave them the permission to leave (after Tawaf-Al-Ifada)
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
Every narration in Sahih al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 6:34