xajax 0.6 beta1 allows remote attackers to obtain sensitive information via a direct request to a .php file, which reveals the installation path in an error message, as demonstrated by xajax_core/plugin_layer/xajaxScriptPlugin.inc.php and certain other files.
http://www.openwall.com/lists/oss-security/2011/06/27/6
http://code.google.com/p/inspathx/source/browse/trunk/paths_vuln/xajax
http://code.google.com/p/inspathx/source/browse/trunk/paths_vuln/%21_README