Jami` at-Tirmidhi 13
جامع الترمذي#13SahihHudhaifah narrated:"Allah's Messenger came to a waste area used by people, so he urinated on it while standing. I brought him the (water for) Wudu. Then I left to be away from him, but he called me until I was behind him. So he performed Wudu and wiped (Masaba) over his Khuff
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Ahmad Muhammad ShakirSahih
Al-AlbaniSahih
Zubair Ali ZaiSahih - Agreed Upon
In-book reference: 1:13