The fr_dhcp_decode function in lib/dhcp.c in FreeRADIUS 2.1.9, in certain non-default builds, does not properly handle the DHCP Relay Agent Information option, which allows remote attackers to cause a denial of service (infinite loop and daemon outage) via a packet that has more than one sub-option. NOTE: some of these details are obtained from third party information.
https://bugzilla.redhat.com/show_bug.cgi?id=639390
https://bugs.freeradius.org/bugzilla/show_bug.cgi?id=77
http://www.openwall.com/lists/oss-security/2010/10/01/8
http://www.openwall.com/lists/oss-security/2010/10/01/3
http://secunia.com/advisories/41621
http://github.com/alandekok/freeradius-server/commit/4dc7800b866f889a1247685bbaa6dd4238a56279