Mont. Code Ann. § 71-3-1303
71-3-1303 Extent of liens
71-3-1303 . Extent of liens. The liens defined in 71-3-1301 and 71-3-1302 are valid against everyone claiming under the debtor, except a purchaser and encumbrancer in good faith and for value.
Mont. Code Ann. § 71-3-1303