N.J. Stat. Ann. § 2A:62-10

If the title to the lands which is the subject of the judgment sought to be opened pursuant to N.J.S.2A:62-8 and N.J.S.2A:62-9, has, by the judgment or in consequence thereof, been conveyed to a purchaser for value or mortgaged to a mortgagee for value, the title shall not be affected by either the opening or vacation of the judgment. The vacation of the judgment shall operate only against the plaintiff named in the judgment, the plaintiff's heirs, executors, and administrators, to compel compensation to the minor, or incapacitated person to the extent of the value of the plaintiff's interest in the affected real property at the time the property was so conveyed or mortgaged.