The problem can be corrected by upgrading the affected package to
version 1.6.7p5-1ubuntu4.4 (for Ubuntu 4.10), 1.6.8p5-1ubuntu2.3 (for
Ubuntu 5.04), or 1.6.8p9-2ubuntu2.2 (for Ubuntu 5.10). In general, a
standard system upgrade is sufficient to effect the necessary changes.
Charles Morris discovered a privilege escalation vulnerability in
sudo. On executing Perl scripts with sudo, various environment
variables that affect Perl's library search path were not cleaned
properly. If sudo is set up to grant limited sudo execution of Perl
scripts to normal users, this could be exploited to run arbitrary
commands as the target user.
This security update also filters out environment variables that can
be exploited similarly with Python, Ruby, and zsh scripts.
Please note that this does not affect the default Ubuntu installation,
or any setup that just grants full root privileges to certain users.