Mass. Gen. Laws ch. 60 § 69A
No petition to vacate a decree of foreclosure entered under section sixty-nine and no proceeding at law or in equity for reversing or modifying such a decree shall be commenced by any person other than the petitioner except within one year after the final entry of the decree if the decree is entered on or after September first, nineteen hundred and forty-five or within one year after said date if the decree was entered prior to said date. If said foreclosure petition was filed for an unoccupied or abandoned building as set forth in sections one and eighty-one A, or there has been a certification pursuant to section 81B that the redemption amount as determined pursuant to section 62 exceeds the assessed value of the parcel, no petition to vacate a decree of foreclosure entered under section sixty-nine and no proceedings at law or equity for reversing or modifying such a decree shall be commenced by any person other than the petitioner except within ninety calendar days after the final entry of the decree, or within one year of the final entry of the decree, if the decree was entered prior to the effective date of this section. For any decree relating to a property which stands in the name of a deceased person or person under guardianship or conservatorship, a petition may be maintained for reversal or modification of such decree up to one year from the date of decree.
Mass. Gen. Laws ch. 60, § 69A