diff --git a/src/cairo-polygon-intersect.c b/src/cairo-polygon-intersect.c
index c900c89..317ece1 100644
--- a/src/cairo-polygon-intersect.c
+++ b/src/cairo-polygon-intersect.c
@@ -1243,6 +1243,9 @@ active_edges (cairo_bo_edge_t		*left,
 		}
 
 		right = right->next;
+
+                if (!right)
+                    return;
 	    } while (1);
 
 	    edges_start_or_continue (left, right, top, polygon);