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B.16.2. RHSA-2011:0256 — Moderate: dhcp security update

Updated dhcp packages that fix one security issue are now available for Red Hat Enterprise Linux 6.
The Red Hat Security Response Team has rated this update as having moderate security impact. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) associated with each description below.
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.
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.