diff --git a/ultralytics/nn/tasks.py b/ultralytics/nn/tasks.py
index 68d4ee65..a30094c9 100644
--- a/ultralytics/nn/tasks.py
+++ b/ultralytics/nn/tasks.py
@@ -379,7 +379,7 @@ class DetectionModel(BaseModel):
 
     def init_criterion(self):
         """Initialize the loss criterion for the DetectionModel."""
-        return E2EDetectLoss(self) if self.end2end else v8DetectionLoss(self)
+        return E2EDetectLoss(self) if getattr(self, "end2end", False) else v8DetectionLoss(self)
 
 
 class OBBModel(DetectionModel):