Index: core/kernel/managers/url_manager.php
===================================================================
--- core/kernel/managers/url_manager.php
+++ core/kernel/managers/url_manager.php
@@ -464,6 +464,11 @@
 		$not_found = $this->Application->ConfigValue('ErrorTemplate');
 		$template = $not_found ? $not_found : 'error_notfound';
 
+		// Avoid recursion, when attempt is made to show 404 page while on the 404 page.
+		if ( $this->Application->GetVar('t') === $template ) {
+			return;
+		}
+
 		$this->Application->QuickRun($template);
 		$this->Application->Done();
 		exit;