---
title: "CVE-2005-0337\n    | Ubuntu"
description: Ubuntu is an open source software operating system that runs from the
  desktop, to the cloud, to all your internet connected things.
url: https://ubuntu.com/security/CVE-2005-0337?format=md
keywords: index, follow
---

# CVE-2005-0337

Publication date 2 May 2005

Last updated 17 July 2025

---

Ubuntu priority

**Medium**

[Why this priority?](https://ubuntu.com/security/cves/about#priority )

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## 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.

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| postfix | 7.04 feisty | Fixed 2.3.3-1 |
| 6.10 edgy | Fixed 2.3.3-1 |
| 6.06 LTS dapper | Fixed 2.2.10-1ubuntu0.1 |

---

* [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)
* [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses)

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2005-0337)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2005-0337)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2005-0337)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2005-0337)

### Other references

* <https://www.cve.org/CVERecord?id=CVE-2005-0337>