sudo 1.6.0 through 1.6.3p7 does not properly clear the environment before calling the mail program, which could allow local users to gain root privileges by modifying environment variables and changing how the mail program is invoked.
https://exchange.xforce.ibmcloud.com/vulnerabilities/7891
http://www.sudo.ws/sudo/alerts/postfix.html
http://www.securityfocus.com/bid/3871
http://www.securityfocus.com/archive/1/250168
http://www.securityfocus.com/advisories/3800
http://www.redhat.com/support/errata/RHSA-2002-013.html
http://www.redhat.com/support/errata/RHSA-2002-011.html
http://www.novell.com/linux/security/advisories/2002_002_sudo_txt.html
http://www.debian.org/security/2002/dsa-101
http://marc.info/?l=bugtraq&m=101120193627756&w=2
http://frontal2.mandriva.com/security/advisories?name=MDKSA-2002:003
http://distro.conectiva.com.br/atualizacoes/?id=a&anuncio=000451