diff --git a/libraries/cms/router/router.php b/libraries/cms/router/router.php
index 3ee6417a0196a..d5a07c2e498e9 100644
--- a/libraries/cms/router/router.php
+++ b/libraries/cms/router/router.php
@@ -590,7 +590,7 @@ protected function processParseRules(&$uri, $stage = self::PROCESS_DURING)
 
 		foreach ($this->_rules['parse' . $stage] as $rule)
 		{
-			$vars += call_user_func_array($rule, array(&$this, &$uri));
+			$vars += (array) call_user_func_array($rule, array(&$this, &$uri));
 		}
 
 		return $vars;