Mon Nedarim 71

If the father heard the neder and made hafara, while before the husband hears, he dies, if she receives Kiddushin that day, the second husband may do Hafara.

Ran explains that this may go according to Beis Hillel. Although he holds that the father's heter would weaken the Neder tot he point that it would be too weak to transfer the remainder to the father, still we say that the second husband may make Hafara. The reason is, the Neder is not transferring from the first husband's jurisdiction to the second husband's jurisdiction. Rather, the second husband is taking over the first husband's position and we consider him just a continuation of the first husband's jurisdiction.