The senior was 22 years old.
"Words cannot express our pain and sorrow," Navy head coach Ken Niumatalolo said. "First and foremost, our deepest condolences to the Forney family. The Navy football brotherhood is not a team, we are a family. We are devastated to have lost one of our brothers. We all loved - and will always love - David. We pray for strength during this most difficult time."
Forney started 13 games at guard for the Midshipmen in 2019 on an offense that led the nation in rushing, averaging 360.5 yards per game.
He was a First-Team American Athletic Conference and First-Team All-East player.
Forney was set to graduate on May 22.