Sunan an-Nasa'i 444
سنن النسائي#444Sahihأَخْبَرَنَا قُتَيْبَةُ، عَنْ سُفْيَانَ، عَنْ عَبْدِ اللَّهِ، - يَعْنِي ابْنَ أَبِي بَكْرٍ - قَالَ عَلَى أَثَرِهِ قَالَ أَبُو عَبْدِ الرَّحْمَنِ وَلَمْ أُتْقِنْهُ عَنْ عُرْوَةَ، عَنْ بُسْرَةَ، قَالَتْ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " مَنْ مَسَّ فَرْجَهُ فَلْيَتَوَضَّأْ " .
It was narrated that Busrah said:"The Messenger of Allah (ﷺ) said: 'Whoever touches his private part, let him perform Wudu
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:
Abu GhuddahSahih
Al-AlbaniSahih
Zubair Ali ZaiSahih
In-book reference: 4:50