Jami` at-Tirmidhi 2720
جامع الترمذي#2720SahihNarrated Ibn 'Umar:that a man gave the Salam to the Prophet (ﷺ) while he was urinating, but the Prophet (ﷺ) did not return the Salam to him
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Ahmad Muhammad ShakirHasan Sahih
Al-AlbaniHasan Sahih
Bashar Awad MaaroufHasan Sahih
Zubair Ali ZaiSahih Muslim
In-book reference: 42:33