diff --git a/framework/Compress/lib/Horde/Compress/Tnef.php b/framework/Compress/lib/Horde/Compress/Tnef.php
index a7fe221161f..2a999c60e86 100644
--- a/framework/Compress/lib/Horde/Compress/Tnef.php
+++ b/framework/Compress/lib/Horde/Compress/Tnef.php
@@ -325,8 +325,8 @@ protected function _extractMapiAttributes($data)
                     $data_len = $id_len + ((4 - ($id_len % 4)) % 4);
                     $this->_logger->debug(sprintf(
                         'TNEF: Named Id: %s',
-                        substr($this->_getx($data, $data_len), $id_len)
-                    ));
+                        substr($this->_getx($data, $data_len)), 0, $id_len)
+                    );
                     break;
 
                 default: