(RHSA-2011:0256) Moderate: dhcp security update

The Dynamic Host Configuration Protocol (DHCP) is a protocol that allows
individual devices on an IP network to get their own network configuration
information, including an IP address, a subnet mask, and a broadcast
address. DHCPv6 is the DHCP protocol version for IPv6 networks.

A flaw was found in the way the dhcpd daemon processed certain DHCPv6
messages for addresses that had previously been declined and marked as
abandoned internally. If a remote attacker sent such messages to dhcpd, it
could cause dhcpd to crash due to an assertion failure if it was running as
a DHCPv6 server. (CVE-2011-0413)

Red Hat would like to thank Internet Systems Consortium for reporting this
issue.

Users running dhcpd as a DHCPv6 server should upgrade to these updated
packages, which contain a backported patch to correct this issue. After
installing this update, all DHCP servers will be restarted automatically.