modules/rlm_unix/rlm_unix.c in FreeRADIUS before 2.2.0, when unix mode is enabled for user authentication, does not properly check the password expiration in /etc/shadow, which allows remote authenticated users to authenticate using an expired password.
https://github.com/alandekok/freeradius-server/commit/1b1ec5ce75e224bd1755650c18ccdaa6dc53e605
http://rhn.redhat.com/errata/RHSA-2013-0134.html
http://rhn.redhat.com/errata/RHBA-2012-0881.html
http://lists.opensuse.org/opensuse-updates/2013-01/msg00079.html
http://lists.opensuse.org/opensuse-updates/2013-01/msg00029.html