I believe a priest now can forgive the sin of abortion.
At one time, the sin had to be told in Confession, brought to the attention of the Bishop, and then a second Confession.
Someone else said this Post is correct. This is the text of Post #11:
[Post by Campion]Abortion incurs a latae sententiae excommunication.
It used to be that priests had to request the faculty to remit the excommunication from the bishop on a case by case basis, so the penitent typically had to confess twice, once to request the faculty and once to receive it.
I believe that now Pope Francis has extended the faculty to remit the penalty to all priests in confession, so it's effectively like confessing any other sin.