diff --git a/src/openrct2-ui/windows/Sign.cpp b/src/openrct2-ui/windows/Sign.cpp
index 64d92db9a0..71f997276d 100644
--- a/src/openrct2-ui/windows/Sign.cpp
+++ b/src/openrct2-ui/windows/Sign.cpp
@@ -177,6 +177,10 @@ rct_window* window_sign_open(rct_windownumber number)
             }
         }
         tile_element++;
+        if (tile_element >= &gTileElements[std::size(gTileElements)])
+        {
+            return nullptr;
+        }
     }
 
     int32_t view_z = tile_element->GetBaseZ();
@@ -230,6 +234,10 @@ static void window_sign_mouseup(rct_window* w, rct_widgetindex widgetIndex)
                     }
                 }
                 tile_element++;
+                if (tile_element >= &gTileElements[std::size(gTileElements)])
+                {
+                    return;
+                }
             }
 
             auto sceneryRemoveAction = LargeSceneryRemoveAction(