When a decree is granted by a probate court authorizing a sale or mortgage of real estate of a deceased person, or of a person under guardianship, the adjudication of the court that the sale or mortgage is required shall be final so far as it may affect any title acquired by virtue of the decree; but nothing contained in this section shall affect the right of the executor, administrator, or guardian to contest the validity of any claim against the estate or ward.
R.I. Gen. Laws § 33-19-5