diff --git a/libraries/Util.php b/libraries/Util.php
index 2a9da68f4c..1188e145be 100644
--- a/libraries/Util.php
+++ b/libraries/Util.php
@@ -2781,6 +2781,20 @@ class Util
         self::cacheUnset('is_grantuser');
     }
 
+    /**
+     * Calculates session cache key
+     *
+     * @return string
+     */
+    public static function cacheKey()
+    {
+        if (isset($GLOBALS['cfg']['Server']['user'])) {
+            return 'server_' . $GLOBALS['server'] . '_' . $GLOBALS['cfg']['Server']['user'];
+        } else {
+            return 'server_' . $GLOBALS['server'];
+        }
+    }
+
     /**
      * Verifies if something is cached in the session
      *
@@ -2790,7 +2804,7 @@ class Util
      */
     public static function cacheExists($var)
     {
-        return isset($_SESSION['cache']['server_' . $GLOBALS['server'] . '_' . $GLOBALS['cfg']['Server']['user']][$var]);
+        return isset($_SESSION['cache'][self::cacheKey()][$var]);
     }
 
     /**
@@ -2804,7 +2818,7 @@ class Util
     public static function cacheGet($var, $callback = null)
     {
         if (self::cacheExists($var)) {
-            return $_SESSION['cache']['server_' . $GLOBALS['server'] . '_' . $GLOBALS['cfg']['Server']['user']][$var];
+            return $_SESSION['cache'][self::cacheKey()][$var];
         } else {
             if ($callback) {
                 $val = $callback();
@@ -2825,7 +2839,7 @@ class Util
      */
     public static function cacheSet($var, $val = null)
     {
-        $_SESSION['cache']['server_' . $GLOBALS['server'] . '_' . $GLOBALS['cfg']['Server']['user']][$var] = $val;
+        $_SESSION['cache'][self::cacheKey()][$var] = $val;
     }
 
     /**
@@ -2837,7 +2851,7 @@ class Util
      */
     public static function cacheUnset($var)
     {
-        unset($_SESSION['cache']['server_' . $GLOBALS['server'] . '_' . $GLOBALS['cfg']['Server']['user']][$var]);
+        unset($_SESSION['cache'][self::cacheKey()][$var]);
     }
 
     /**