The run_coprocess function in pam_xauth.c in the pam_xauth module in Linux-PAM (aka pam) before 1.1.2 does not check the return values of the setuid, setgid, and setgroups system calls, which might allow local users to read arbitrary files by executing a program that relies on the pam_xauth PAM check.
https://sourceforge.net/tracker/?func=detail&aid=3028213&group_id=6663&atid=106663
https://bugzilla.redhat.com/show_bug.cgi?id=637898
http://www.vupen.com/english/advisories/2011/0606
http://www.vmware.com/security/advisories/VMSA-2011-0004.html
http://www.securityfocus.com/archive/1/516909/100/0/threaded
http://www.redhat.com/support/errata/RHSA-2010-0891.html
http://www.redhat.com/support/errata/RHSA-2010-0819.html
http://www.openwall.com/lists/oss-security/2010/09/24/2
http://www.mandriva.com/security/advisories?name=MDVSA-2010:220
http://security.gentoo.org/glsa/glsa-201206-31.xml
http://secunia.com/advisories/49711
http://openwall.com/lists/oss-security/2010/10/25/2
http://openwall.com/lists/oss-security/2010/09/27/7
http://openwall.com/lists/oss-security/2010/09/27/5
http://openwall.com/lists/oss-security/2010/09/27/4
http://openwall.com/lists/oss-security/2010/09/27/10
http://openwall.com/lists/oss-security/2010/09/21/8
http://openwall.com/lists/oss-security/2010/09/21/3
http://openwall.com/lists/oss-security/2010/08/16/2
http://lists.vmware.com/pipermail/security-announce/2011/000126.html