The Book of Pilgrimage
وَحَدَّثَنِيهِ عَلِيُّ بْنُ خَشْرَمٍ، أَخْبَرَنَا عِيسَى بْنُ يُونُسَ، عَنِ ابْنِ جُرَيْجٍ، بِهَذَا الإِسْنَادِ وَفِي رِوَايَتِهِ قَالَتْ لاَ أَىْ بُنَىَّ إِنَّ نَبِيَّ اللَّهِ صلى الله عليه وسلم أَذِنَ لِظُعُنِهِ .This hadith has been narrated by Ibn Juraij with the same chain of transmitters, and In his narration (the words are):" She (Asma') said: My son, Allah's Apostle (ﷺ) granted permission to women
From Sahih Muslim, whose reports the scholars accept as authentic.