Multiple vulnerabilities has been found and corrected in sudo:

A a patch for parse.c in sudo does not properly interpret a system
group (aka %group) in the sudoers file during authorization decisions
for a user who belongs to that group, which allows local users to
leverage an applicable sudoers file and gain root privileges via a sudo
command. NOTE: this vulnerability exists because of a CVE-2009-0034
regression (CVE-2011-0008).

check.c in sudo 1.7.x before 1.7.4p5, when a Runas group is configured,
does not require a password for command execution that involves a
gid change but no uid change, which allows local users to bypass an
intended authentication requirement via the -g option to a sudo command
(CVE-2011-0010).

Packages for 2009.0 are provided as of the Extended Maintenance
Program. Please visit this link to learn more:
http://store.mandriva.com/product_info.php?cPath=149&products_id=490

The updated packages have been upgraded to the latest versions
(1.7.4p6) which is not affected by these issues.