pua_dialoginfo: safety check for request pointer

src/modules/pua_dialoginfo/pua_dialoginfo.c

@@ -580,9 +580,10 @@ static void __dialog_sendpublish(
 
 	if(use_pubruri_avps
 			&& (refresh_pubruri_avps_flag > -1
-					|| (request->flags
-							& (1U << (unsigned int)
-											refresh_pubruri_avps_flag)))) {
+					|| (request
+							&& (request->flags
+									& (1U << (unsigned int)
+													refresh_pubruri_avps_flag))))) {
 		lock_release(&dlginfo->lock);
 	}
 }