Sayyiduna Anas (may Allah be pleased with him) says: I prayed behind the Messenger of Allah (peace and blessings be upon him) and he recited qunut; I prayed behind Sayyiduna Umar (may Allah be pleased with him) and he too recited qunut; and I prayed behind Sayyiduna Uthman (may Allah be pleased with him) and he too recited qunut.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 3107