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.
A denial of service flaw was found in the way the dhcpd daemon handled DHCP request packets when regular expression matching was used in "/etc/dhcp/dhcpd.conf". A remote attacker could use this flaw to crash dhcpd. (CVE-2011-4539)
Users of DHCP 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.