Amazon Linux AMI Security Advisory: ALAS-2013-157
Advisory Release Date: 2014-09-15 22:31 Pacific
A flaw was found in the way the dhcpd daemon handled the expiration time of IPv6 leases. If dhcpd's configuration was changed to reduce the default IPv6 lease time, lease renewal requests for previously assigned leases could cause dhcpd to crash. (CVE-2012-3955 )
Run yum update dhcp to update your system.