Sahih al-Bukhari 5936
Sahih al-Bukhari · Book 77: Dress · The use of false hair
Narrated Asma':
حَدَّثَنَا آدَمُ ، حَدَّثَنَا شُعْبَةُ ، عَنْ هِشَامِ بْنِ عُرْوَةَ ، عَنِ امْرَأَتِهِ، فَاطِمَةَ عَنْ أَسْمَاءَ بِنْتِ أَبِي بَكْرٍ ، قَالَتْ لَعَنَ النَّبِيُّ صلى الله عليه وسلم الْوَاصِلَةَ وَالْمُسْتَوْصِلَةَ.
(the daughter of Abu Bakr) Allah's Messenger (ﷺ) has cursed such a lady as artificially lengthening (her or someone else's) hair or gets her hair lengthened.