Nedarim 86B

אלא אמר רב אשי: שאני קונמות, דכי קדושת הגוף דמי, וכדרבא.

Rather, Rav Ashi said that this is the reason Shmuel ruled in accordance with the opinion of R' Yoḥanan ben Nuri: Although a person cannot consecrate an entity that has not yet come into the world, konamot are different. They are stringent and take effect in all cases, as their prohibited status is considered akin to inherent sanctity. When one person prohibits another from deriving benefit from a particular item by means of a konam, the forbidden item is treated as if it has inherent sanctity. It cannot be redeemed and can never become permitted. Because of its severity, a woman can forbid her handiwork to her husband by means of a konam, even though she is obligated to hand over the fruits of her labor to him. And this is in accordance with the opinion of Rava.

דאמר רבא: הקדש, חמץ ושחרור ⁠— מפקיעין מידי שעבוד.

As Rava said: Consecration of an item to the Temple, becoming subject to the prohibition of leavened bread on Passover, and the emancipation of a slave abrogate any lien that exists upon them. The lien on that property does not prevent the consecration, the prohibition of leavened bread, or the emancipation of the slave from taking effect. In all 3 cases, the debtor loses his ownership of the liened property. The same halakha applies to a konam, whose prohibition has the severity of inherent sanctity. Even though the husband has a right to his wife’s handiwork, which could be described as a lien on her hands, that lien is abrogated when she renders her handiwork forbidden to him by means of a konam, and therefore the vow must be nullified.