Jami` at-Tirmidhi 1528
جامع الترمذي#1528Da'ifNarrated 'Uqbah bin 'Amir:That the Messenger of Allah (ﷺ) said: "The atonement of a vow when it is not specified is the atonement of an oath
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Ahmad Muhammad ShakirDaif
Al-AlbaniDaif
Zubair Ali ZaiDaif
In-book reference: 20:6