diff --git a/wp-admin/admin.php b/wp-admin/admin.php
index 6d1a183ed..202fd2c9e 100644
--- a/wp-admin/admin.php
+++ b/wp-admin/admin.php
@@ -45,7 +45,7 @@ require(ABSPATH . '/wp-admin/menu.php');
 // Handle plugin admin pages.
 if (isset($_GET['page'])) {
 	$plugin_page = stripslashes($_GET['page']);
-	$plugin_page = plugin_basename($_GET['page']);
+	$plugin_page = plugin_basename($plugin_page);
 	$page_hook = get_plugin_page_hook($plugin_page, $pagenow);
 
 	if ( $page_hook ) {