diff --git a/libraries/core.lib.php b/libraries/core.lib.php
index b21ea2bf22..0614dee5e8 100644
--- a/libraries/core.lib.php
+++ b/libraries/core.lib.php
@@ -442,11 +442,16 @@ function PMA_arrayMergeRecursive()
  */
 function PMA_arrayWalkRecursive(&$array, $function, $apply_to_keys_also = false)
 {
+    static $walked_keys = array();
     static $recursive_counter = 0;
     if (++$recursive_counter > 1000) {
         PMA_fatalError(__('possible deep recursion attack'));
     }
     foreach ($array as $key => $value) {
+        if (isset($walked_keys[$key])) {
+            continue;
+        }
+
         if (is_array($value)) {
             PMA_arrayWalkRecursive($array[$key], $function, $apply_to_keys_also);
         } else {
@@ -458,6 +463,9 @@ function PMA_arrayWalkRecursive(&$array, $function, $apply_to_keys_also = false)
             if ($new_key != $key) {
                 $array[$new_key] = $array[$key];
                 unset($array[$key]);
+                $walked_keys[$new_key] = true;
+            } else {
+                $walked_keys[$key] = true;
             }
         }
     }
diff --git a/test/libraries/core/PMA_array_test.php b/test/libraries/core/PMA_array_test.php
index 81a18f423b..86ffcf2c3c 100644
--- a/test/libraries/core/PMA_array_test.php
+++ b/test/libraries/core/PMA_array_test.php
@@ -369,8 +369,8 @@ class PMA_Array_Test extends PHPUnit_Framework_TestCase
             'key3'=>'val3'
         );
         $target = array(
-            "key1"=>'val1',
-            'key2'=>array('skey1'=>'sval1', 'skey2'=>'sval2'),
+            "key1"=>'v\\al1',
+            'key2'=>array('s\\key1'=>'sval1', 'skey2'=>'sval2'),
             'key3'=>'val3'
         );