Narrated 'Uqba bin 'Aamir (RA):
Allah's Mssenger (ﷺ) said: "The atonement for a vow (Nadhr) is (the same as) the atonement an oath (Yamin)." [Reported by Muslim]. at-Tirmidhi added, "If he did not specify it." [And he graded it Sahih (authentic)]. (AR)
Reference (AR): Bulugh al-Maram 1385 (AR)
In-book reference (AR): Book 13, Hadith 12 (AR)
English translation (AR): Book 13, Hadith 1385 (AR)