§ 1. Where a number of persons conspire together to commit an offence, and accomplices are not expressly mentioned in the law or precept, if ferendae sententiae penalties were constituted for the principal offender, then the others are subject to the same penalties or to other penalties of the same or a lesser gravity. § 2. In the case of a latae sententiae penalty attached to an offence, accomplices, even though not mentioned in the law or precept, incur the same penalty if, without their assistance, the crime would not have been committed, and if the penalty is of such a nature as to be able to affect them; otherwise, they can be punished with ferendae sententiae penalties.
Source: Code of Canon Law (Vatican.va)