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.
https://exchange.xforce.ibmcloud.com/vulnerabilities/64636
https://bugzilla.redhat.com/show_bug.cgi?id=668879
http://www.vupen.com/english/advisories/2011/0362
http://www.vupen.com/english/advisories/2011/0212
http://www.vupen.com/english/advisories/2011/0199
http://www.vupen.com/english/advisories/2011/0195
http://www.vupen.com/english/advisories/2011/0182
http://www.vupen.com/english/advisories/2011/0089
http://www.ubuntu.com/usn/USN-1046-1
http://www.sudo.ws/sudo/alerts/runas_group_pw.html
http://www.sudo.ws/repos/sudo/rev/fe8a94f96542
http://www.sudo.ws/repos/sudo/rev/07d1b0ce530e
http://www.securityfocus.com/bid/45774
http://www.redhat.com/support/errata/RHSA-2011-0599.html
http://www.mandriva.com/security/advisories?name=MDVSA-2011:018
http://slackware.com/security/viewer.php?l=slackware-security&y=2011&m=slackware-security.593654
http://security.gentoo.org/glsa/glsa-201203-06.xml
http://secunia.com/advisories/43282
http://secunia.com/advisories/43068
http://secunia.com/advisories/42968
http://secunia.com/advisories/42949
http://secunia.com/advisories/42886
http://openwall.com/lists/oss-security/2011/01/12/3
http://openwall.com/lists/oss-security/2011/01/12/1
http://openwall.com/lists/oss-security/2011/01/11/3
http://lists.opensuse.org/opensuse-security-announce/2011-01/msg00006.html
http://lists.fedoraproject.org/pipermail/package-announce/2011-January/053341.html
http://lists.fedoraproject.org/pipermail/package-announce/2011-January/053263.html