The mailconf module in Linuxconf 1.24, and other versions before 1.28, on Conectiva Linux 6.0 through 8, and possibly other distributions, generates the Sendmail configuration file (sendmail.cf) in a way that configures Sendmail to run as an open mail relay, which allows remote attackers to send Spam email.
http://www.securityfocus.com/bid/6118
http://www.iss.net/security_center/static/10554.php
http://distro.conectiva.com.br/atualizacoes/?id=a&anuncio=000544