The Messenger of Allah ﷺ said, "When one of you wakes from sleep, he should not put his hand into the water for wudu until he has washed it, for none of you knows where his hand spent the night."
وقال رسول الله ﷺ إذا استيقظ أحدكم من نومه فلا يضع يده في الوضوء حتى يغسلها إنه لا يدري أحدكم أين باتت يده
This is also sahih, and it is in the Individual Manuscript (Sahifah) under number 69. The two sheikhs did not narrate it through the route of the Sahifah. Rather, Bukhari narrated it, with similar wording, together with hadith 8179 in a single sequence, from the recension of Aaraj, 329-331 Fath. Muslim narrated it through other routes, not the route of the Sahifah and not the recension of Aaraj, 91-92 Bulaq. It has already occurred, with similar wording, through several routes, including 7280, 7508, 7590, 7660.Al-Wadu, with the wa sound vowelized as fatha, is the water with which one performs wudu.