The Messenger of Allah ﷺ said, "Allah does not accept the prayer of any of you when he has broken his wudu until he performs wudu."
وقال رسول الله ﷺ لا يقبل الله صلاة أحدكم إذا أحدث حتى يتوضأ
This is a sahih hadith, narrated by Muslim, volume 1, pages 140-141, with the wording, "The prayer of any of you is not accepted if he passes wind until he performs wudu," in the chapter on purification, from Muhammad bin Rafi.Bukhari narrated it in the chapter on purification from Ishaq bin Ibrahim, and in the chapter on avoiding legal ruses from Ishaq bin Nasr.Abu Dawud narrated it in the chapter on purification from Ahmad bin Hanbal, and Tirmidhi narrated it in the chapter on purification from Mahmud bin Ghaylan.