=========================================================================Ubuntu Security Notice USN-1309-1
December 15, 2011

isc-dhcp vulnerability
=========================================================================
A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 11.10
- Ubuntu 11.04

Summary:

DHCP could be made to crash if it received specially crafted network
traffic.

Software Description:
- isc-dhcp: DHCP server and client

Details:

It was discovered that the DHCP server incorrectly handled certain
malformed packets when configured to evaluate regular expressions. A remote
attacker could use this issue to cause DHCP to crash, resulting in a denial
of service.

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 11.10:
  isc-dhcp-server                 4.1.1-P1-17ubuntu10.1

Ubuntu 11.04:
  isc-dhcp-server                 4.1.1-P1-15ubuntu9.3

In general, a standard system update will make all the necessary changes.

References:
  https://ubuntu.com/security/notices/USN-1309-1
  CVE-2011-4539

Package Information:
  https://launchpad.net/ubuntu/+source/isc-dhcp/4.1.1-P1-17ubuntu10.1
  https://launchpad.net/ubuntu/+source/isc-dhcp/4.1.1-P1-15ubuntu9.3