§1. The local ordinary can dispense his own subjects residing anywhere and all actually present in his own territory from all impediments of ecclesiastical law except those whose dispensation is reserved to the Apostolic See.
§2. Impediments whose dispensation is reserved to the Apostolic See are: 1/ the impediment arising from sacred orders or from a public perpetual vow of chastity in a religious institute of pontifical right; 2/ the impediment of crime mentioned in can. 1090.
§3. A dispensation is never given from the impediment of consanguinity in the direct line or in the second degree of the collateral line.
Source: Code of Canon Law (Vatican.va)