diff --git a/sql/auth/sql_authentication.cc b/sql/auth/sql_authentication.cc
index 0936081f1e5..02b0e7ff803 100644
--- a/sql/auth/sql_authentication.cc
+++ b/sql/auth/sql_authentication.cc
@@ -1067,6 +1067,7 @@ static bool parse_com_change_user_packet(MPVIO_EXT *mpvio, size_t packet_length)
   {
     if (mpvio->charset_adapter->init_client_charset(uint2korr(ptr)))
       DBUG_RETURN(1);
+    ptr= ptr + 2;
   }
 
   /* Convert database and user names to utf8 */
@@ -1110,12 +1111,13 @@ static bool parse_com_change_user_packet(MPVIO_EXT *mpvio, size_t packet_length)
   const char *client_plugin;
   if (protocol->has_client_capability(CLIENT_PLUGIN_AUTH))
   {
-    client_plugin= ptr + 2;
+    client_plugin= ptr;
     if (client_plugin >= end)
     {
       my_message(ER_UNKNOWN_COM_ERROR, ER(ER_UNKNOWN_COM_ERROR), MYF(0));
       DBUG_RETURN(1);
     }
+    ptr= ptr + strlen(client_plugin) + 1;
   }
   else
     client_plugin= native_password_plugin_name.str;