---
title: "CVE-2007-4321\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-2007-4321?format=md
keywords: index, follow
---

# CVE-2007-4321

Publication date 14 August 2007

Last updated 17 July 2025

---

Ubuntu priority

**Medium**

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

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## Description

fail2ban 0.8 and earlier does not properly parse sshd log files, which
allows remote attackers to add arbitrary hosts to the /etc/hosts.deny file
and cause a denial of service by adding arbitrary IP addresses to the sshd
log file, as demonstrated by logging in via ssh with a client protocol
version identification containing an IP address string, a different vector
than CVE-2006-6302.

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| fail2ban | 9.10 karmic | Fixed 0.8.0-4 |
| 9.04 jaunty | Fixed 0.8.0-4 |
| 8.10 intrepid | Fixed 0.8.0-4 |
| 8.04 LTS hardy | Fixed 0.8.0-4 |
| 7.10 gutsy | Fixed 0.8.0-4 |
| 7.04 feisty | Ignored end of life, was needed |
| 6.10 edgy | Ignored end of life, was needed |
| 6.06 LTS dapper | Ignored end of life |

---

* [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)
* [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses)
* [Patch details](https://ubuntu.com/security/CVE-2007-4321?format=md#patch-details)

### Patch details

For informational purposes only. We recommend not to cherry-pick updates. [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)

| Package | Patch details |
| --- | --- |
| fail2ban | * Vendor:   <http://www.debian.org/security/2008/dsa-1456> |

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2007-4321)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2007-4321)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2007-4321)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2007-4321)

### Other references

* <https://www.cve.org/CVERecord?id=CVE-2007-4321>