XChat IRC client allows remote attackers to execute arbitrary commands via a /dns command on a host whose DNS reverse lookup contains shell metacharacters.
http://www.securityfocus.com/bid/4376
http://www.redhat.com/support/errata/RHSA-2002-124.html
http://www.redhat.com/support/errata/RHSA-2002-097.html
http://www.linux-mandrake.com/en/security/2002/MDKSA-2002-051.php
http://www.iss.net/security_center/static/8704.php
http://marc.info/?l=bugtraq&m=101725430425490&w=2
http://distro.conectiva.com.br/atualizacoes/?id=a&anuncio=000526