Did Judas die by hanging or by falling onto some rocks?

Matthew 27:5 tells us that Judas died by hanging himself. Acts 1:18 tells us that Judas fell onto some rocks and his body burst open. Is there a contradiction here?

No. Both accounts are true. Apparently Judas first hanged himself. Then, at some point, the rope either broke or loosened so that his body slipped from it and fell to the rocks below and burst open. (Some have suggested that Judas didn't do a very good job of tying the noose.) Neither account alone is complete. Taken together, we have a full picture of what happened to Judas.