diff --git a/src/mapserver/qgswmsserver.cpp b/src/mapserver/qgswmsserver.cpp
index 7bb920e1441..420c746096f 100644
--- a/src/mapserver/qgswmsserver.cpp
+++ b/src/mapserver/qgswmsserver.cpp
@@ -101,6 +101,8 @@ void QgsWMSServer::executeRequest()
   {
     QgsDebugMsg( "unable to find 'REQUEST' parameter, exiting..." );
     mRequestHandler->sendServiceException( QgsMapServiceException( "OperationNotSupported", "Please check the value of the REQUEST parameter" ) );
+    cleanupAfterRequest();
+    return;
   }
 
   //version