Mansur 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."
أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا جَرِيرٌ، عَنْ مَنْصُورٍ، عَنِ الْحَكَمِ، عَنْ مِقْسَمٍ، عَنْ أُمِّ سَلَمَةَ، قَالَتْ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم يُوتِرُ بِخَمْسٍ وَبِسَبْعٍ لاَ يَفْصِلُ بَيْنَهَا بِسَلاَمٍ وَلاَ بِكَلاَمٍ .
Nesai
The Book of Qiyam Al-Lail (The Night Prayer) and Voluntary Prayers During the Day • Hadith 1714