CVE-2005-0337: Red Hat Enterprise Linux

High severity, CVSS 7.5. EPSS: 2.8% chance of exploitation in the next 30 days.

Postfix 2.1.3, when /proc/net/if_inet6 is not available and permit_mx_backup is enabled in smtpd_recipient_restrictions, allows remote attackers to bypass e-mail restrictions and perform mail relaying by sending mail to an IPv6 hostname.

Affected products

• Red Hat Enterprise Linux: version 4.0 only
• Red Hat Enterprise Linux Desktop: version 4.0 only
• Suse Suse Linux: version 8.0 only; version 8.1 only; version 8.2 only; version 9.0 only; version 9.1 only; version 9.2 only
• Wietse Venema Postfix: version 2.1.3 only

Published 2005-05-02. Last modified 2026-06-16.