The following bug has been fixed:
[-] Fixed moderate security issue with privilege escalation. Parallels Plesk Panel versions 9.x-11.x with Apache web server running mod_php, mod_perl, mod_python, etc. is vulnerable to authenticated user privilege escalation. Authenticated users are users that have login to Parallels Plesk Panel (such as f.e. your customers, resellers, or your employees).
Parallels Plesk Panel instances with Apache web server configured with Fast CGI (PHP, perl, python, etc) or CGI (PHP, perl, python, etc) are NOT vulnerable.
More details in article Public issues VU#310500 and CVE-2013-0132, CVE-2013-0133
This MU is recommended for all Parallels Plesk Panel users.