USN-642-1: Postfix vulnerability

Referenced CVEs: CVE-2008-3889Description: 
Ubuntu Security Notice USN-642-1 September 10, 2008
postfix vulnerability

A security issue affects the following Ubuntu releases:

Ubuntu 7.10
Ubuntu 8.04 LTS

This advisory also applies to the corresponding versions of
Kubuntu, Edubuntu, and Xubuntu.

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

Ubuntu 7.10:
postfix 2.4.5-3ubuntu1.3

Ubuntu 8.04 LTS:
postfix 2.5.1-2ubuntu1.2

In general, a standard system upgrade is sufficient to effect the
necessary changes.

Details follow:

Wietse Venema discovered that Postfix leaked internal file descriptors
when executing non-Postfix commands. A local attacker could exploit
this to cause Postfix to run out of descriptors, leading to a denial
of service.