ʿAlqamah reports:

Ibn Masʿūd and [the rest of] the Companions of the Prophet ﷺ used to say the qunūt supplication before bowing in the witr prayer.

Ibn Abī Shaybah, Al-Muṣannaf ḥadīth 6911, and others.

Al-Albānī states, commenting on the chain of transmission of the narration in Al-Maṣannaf:

This is a good (jayyid) chain of transmission, and it comforms to the conditions stipulated by Muslim (for his Ṣaḥīḥ) … in summary: that which is authentic and established from the Companions is qunūt before bowing in the witr prayer.

Irwāʾ Al-Ghalīl 2:166.