Sunan an-Nasa'i 1714
سنن النسائي#1714SahihMansur reported from Al-Hakam, from Miqsam, that Umm Salamah said:"The Messenger of Allah (ﷺ) used to pray witr with five and seven rak'ahs which he did not separate with any taslim nor talk
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Abu GhuddahSahih
Al-AlbaniSahih
Zubair Ali ZaiSahih
In-book reference: 20:117