diff --git a/include/mpu_wrappers.h b/include/mpu_wrappers.h
index 3b4738e962..b1b35d2ba8 100644
--- a/include/mpu_wrappers.h
+++ b/include/mpu_wrappers.h
@@ -249,6 +249,9 @@
         #if ( ( configUSE_MPU_WRAPPERS_V1 == 0 ) && ( configENABLE_ACCESS_CONTROL_LIST == 1 ) )
 
             #define vGrantAccessToTask( xTask, xTaskToGrantAccess )                        vGrantAccessToKernelObject( ( xTask ), ( int32_t ) ( xTaskToGrantAccess ) )
+
+/* A privileged task must revoke access to the object before deletion,
+ * otherwise index reuse may result in accidental permissions. */
             #define vRevokeAccessToTask( xTask, xTaskToRevokeAccess )                      vRevokeAccessToKernelObject( ( xTask ), ( int32_t ) ( xTaskToRevokeAccess ) )
 
             #define vGrantAccessToSemaphore( xTask, xSemaphoreToGrantAccess )              vGrantAccessToKernelObject( ( xTask ), ( int32_t ) ( xSemaphoreToGrantAccess ) )