diff --git a/pcbnew/pad.h b/pcbnew/pad.h
index 6232e7fad1..c90ff71a05 100644
--- a/pcbnew/pad.h
+++ b/pcbnew/pad.h
@@ -744,13 +744,13 @@ public:
 
     const ZONE_LAYER_OVERRIDE& GetZoneLayerOverride( PCB_LAYER_ID aLayer ) const
     {
-        return m_zoneLayerOverrides[ aLayer ];
+        return m_zoneLayerOverrides.at( aLayer );
     }
 
     void SetZoneLayerOverride( PCB_LAYER_ID aLayer, ZONE_LAYER_OVERRIDE aOverride )
     {
         std::unique_lock<std::mutex> cacheLock( m_zoneLayerOverridesMutex );
-        m_zoneLayerOverrides[ aLayer ] = aOverride;
+        m_zoneLayerOverrides.at( aLayer ) = aOverride;
     }
 
 #if defined(DEBUG)
diff --git a/pcbnew/pcb_track.h b/pcbnew/pcb_track.h
index aa6cb4e263..f997b489ae 100644
--- a/pcbnew/pcb_track.h
+++ b/pcbnew/pcb_track.h
@@ -567,13 +567,13 @@ public:
 
     const ZONE_LAYER_OVERRIDE& GetZoneLayerOverride( PCB_LAYER_ID aLayer ) const
     {
-        return m_zoneLayerOverrides[ aLayer ];
+        return m_zoneLayerOverrides.at( aLayer );
     }
 
     void SetZoneLayerOverride( PCB_LAYER_ID aLayer, ZONE_LAYER_OVERRIDE aOverride )
     {
         std::unique_lock<std::mutex> cacheLock( m_zoneLayerOverridesMutex );
-        m_zoneLayerOverrides[ aLayer ] = aOverride;
+        m_zoneLayerOverrides.at( aLayer ) = aOverride;
     }
 
 protected: