A security issue affects the following Ubuntu releases:
Ubuntu 4.10 (Warty Warthog)
The following packages are affected:
The problem can be corrected by upgrading the affected package to
version 2.1.3-1ubuntu17.1. In general, a standard system upgrade is
sufficient to effect the necessary changes.
Jean-Samuel Reynaud noticed a programming error in the IPv6 handling
code of Postfix when /proc/net/if_inet6 is not available (which is the
case in Ubuntu since Postfix runs in a chroot). If "permit_mx_backup"
was enabled in the "smtpd_recipient_restrictions", Postfix turned into
an open relay, i. e. erroneously permitted the delivery of arbitrary
mail to any MX host which has an IPv6 address.