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.
It was discovered that the DHCP client daemon, dhclient, did not sufficiently sanitize certain options provided in DHCP server replies, such as the client hostname. A malicious DHCP server could send such an option with a specially-crafted value to a DHCP client. If this option's value was saved on the client system, and then later insecurely evaluated by a process that assumes the option is trusted, it could lead to arbitrary code execution with the privileges of that process. (CVE-2011-0997)
Red Hat would like to thank Sebastian Krahmer of the SuSE Security Team for reporting this issue.
All dhclient users should upgrade to these updated packages, which contain a backported patch to correct this issue.