A vulnerability was discovered in SyntaxCMS testing code that can be exploited to include a remote file. If you're site is running with php's register_globals turned on, and allow_url_fopen turned on, with PHP 4.3.0 or later, you may be vulnerable. We've prepared a patch to fix the vulnerability, which you can find here.
If you can't update from CVS or patch your system you can also disable register_globals and allow_url_fopen, delete the public/admin/testing directory, or drop the following .htaccess file into public/admin/testing/tests if you are using Apache: