---
title: "CVE-2017-6519\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-2017-6519?format=md
keywords: index, follow
---

# CVE-2017-6519

Publication date 30 April 2017

Last updated 25 August 2025

---

Ubuntu priority

**Low**

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

## Cvss 3 Severity Score

**9.1 · Critical**

[Score breakdown](https://ubuntu.com/security/CVE-2017-6519?format=md#impact-score)

Toggle side navigation

## Description

avahi-daemon in Avahi through 0.6.32 and 0.7 inadvertently responds to IPv6
unicast queries with source addresses that are not on-link, which allows
remote attackers to cause a denial of service (traffic amplification) and
may cause information leakage by obtaining potentially sensitive
information from the responding device via port-5353 UDP packets. NOTE:
this may overlap CVE-2015-2809.

## Mitigation

Block udp port 5353 at perimeter firewall

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| avahi | 18.10 cosmic | Fixed 0.7-4ubuntu2.1 |
| 18.04 LTS bionic | Fixed 0.7-3.1ubuntu1.2 |
| 17.10 artful | Ignored end of life |
| 17.04 zesty | Ignored end of life |
| 16.10 yakkety | Ignored end of life |
| 16.04 LTS xenial | Fixed 0.6.32~rc+dfsg-1ubuntu2.3 |
| 14.04 LTS trusty | Fixed 0.6.31-4ubuntu1.3 |
| 12.04 LTS precise | 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-2017-6519?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 |
| --- | --- |
| avahi | * Upstream:   [e111def](https://github.com/lathiat/avahi/commit/e111def44a7df4624a4aa3f85fe98054bffb6b4f) |

## Severity score breakdown

CVSS version:
CVSS v3.0

**Base score**

9.1 · Critical

* Base metrics

  | Parameter | Value |
  | --- | --- |
  | Attack vector | Network |
  | Attack complexity | Low |
  | Privileges required | None |
  | User interaction | None |
  | Scope | Unchanged |
  | Confidentiality impact | High |
  | Integrity impact | None |
  | Availability impact | High |
* Scores

  | Parameter | Value |
  | --- | --- |
  | Base score | 9.1 · Critical |
  | Exploitability score | - |
  | Impact score | - |

**Vector:** CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-6519)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2017-6519)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2017-6519)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2017-6519)

### Related Ubuntu Security Notices (USN)

+ [USN-3876-1](https://usn.ubuntu.com/USN-3876-1)
+ Avahi vulnerabilities
+ 31 January 2019

+ [USN-3876-2](https://usn.ubuntu.com/USN-3876-2)
+ Avahi vulnerabilities
+ 31 January 2019

### Other references

* <https://www.secfu.net/advisories>
* <https://www.kb.cert.org/vuls/id/550620>
* <https://www.cve.org/CVERecord?id=CVE-2017-6519>