"If anyone tells you that the Messenger of Allah urinated while standing, do not believe him, for I (always) saw him urinating while sitting down."
Sunan Ibn Majah Book 1, Hadith 41
← Previous Hadith The Messenger of Allah came to the garbage dump of some people and urinated while standing up. (Hasan)

Shu'bah said: "That day, 'Asim said: 'Amash reported this from Abu Wa'il, from Hudhaifah, but he did not remember it (correctly). So I asked Mansur about it, and he narrated it to me from Abu Wa'il, from Hudhaifah, that the Prophet came to a dump of some people and urinated while standing.'"

Sunan Ibn Majah Book 1, Hadith 40 Next Hadith → "The Messenger of Allah saw me urinating while standing, and he said: 'O 'Umar, do not urinate standing up.' So I never urinated whilst standing after that."

Sunan Ibn Majah Book 1, Hadith 42