Sunan Ibn Majah, Chapter: The Chapters of Purification and its Sunnah

from Asim, from Abu Wail, from Mughirah bin Shubah that the Messenger of Allah (saw) came to the garbage dump of some people and urinated standing up. (Hasan) Shubah 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 (saw) came to a dump of some people and urinated standing up.'"