CVE-2017-6519 Denial of service in n/a
Critical 9.1
Published
Updated
Check this codebase for CVE-2017-6519 and fix it if it is affected.
What it is: CVE-2017-6519 is a critical denial of service vulnerability in Canonical Ubuntu Linux, published on 1 May 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2017-6519 in the wild and no public exploit code.
Affected product: Canonical Ubuntu Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.
Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.
Reference: https://insights.sbomify.com/CVE-2017-6519/ (Markdown: https://insights.sbomify.com/CVE-2017-6519/index.md)
Remote attackers can cause denial of service via traffic amplification and potentially leak sensitive information from Avahi mDNS responders.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2017-6519?
CVE-2017-6519 is a critical denial of service vulnerability in Canonical Ubuntu Linux, published on 1 May 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-346
Which versions are affected by CVE-2017-6519?
It affects 2 products.
Linux distribution packages (40)
avahi Red Hat:enterprise_linux:7::client | All versions | 0:0.6.31-20.el7 |
avahi-autoipd Red Hat:enterprise_linux:7::client | All versions | 0:0.6.31-20.el7 |
avahi-compat-howl Red Hat:enterprise_linux:7::client | All versions | 0:0.6.31-20.el7 |
avahi-compat-howl-devel Red Hat:enterprise_linux:7::client | All versions | 0:0.6.31-20.el7 |
avahi-compat-libdns_sd Red Hat:enterprise_linux:7::client | All versions | 0:0.6.31-20.el7 |
avahi-compat-libdns_sd-devel Red Hat:enterprise_linux:7::client | All versions | 0:0.6.31-20.el7 |
avahi-debuginfo Red Hat:enterprise_linux:7::client | All versions | 0:0.6.31-20.el7 |
avahi-devel Red Hat:enterprise_linux:7::client | All versions | 0:0.6.31-20.el7 |
avahi-dnsconfd Red Hat:enterprise_linux:7::client | All versions | 0:0.6.31-20.el7 |
avahi-glib Red Hat:enterprise_linux:7::client | All versions | 0:0.6.31-20.el7 |
avahi-glib-devel Red Hat:enterprise_linux:7::client | All versions | 0:0.6.31-20.el7 |
avahi-gobject Red Hat:enterprise_linux:7::client | All versions | 0:0.6.31-20.el7 |
avahi-gobject-devel Red Hat:enterprise_linux:7::client | All versions | 0:0.6.31-20.el7 |
avahi-libs Red Hat:enterprise_linux:7::client | All versions | 0:0.6.31-20.el7 |
avahi-qt3 Red Hat:enterprise_linux:7::client | All versions | 0:0.6.31-20.el7 |
avahi-qt3-devel Red Hat:enterprise_linux:7::client | All versions | 0:0.6.31-20.el7 |
avahi-qt4 Red Hat:enterprise_linux:7::client | All versions | 0:0.6.31-20.el7 |
avahi-qt4-devel Red Hat:enterprise_linux:7::client | All versions | 0:0.6.31-20.el7 |
avahi-tools Red Hat:enterprise_linux:7::client | All versions | 0:0.6.31-20.el7 |
avahi-ui Red Hat:enterprise_linux:7::client | All versions | 0:0.6.31-20.el7 |
avahi-ui-devel Red Hat:enterprise_linux:7::client | All versions | 0:0.6.31-20.el7 |
avahi-ui-gtk3 Red Hat:enterprise_linux:7::client | All versions | 0:0.6.31-20.el7 |
avahi-ui-tools Red Hat:enterprise_linux:7::client | All versions | 0:0.6.31-20.el7 |
avahi Red Hat:enterprise_linux:7::computenode | All versions | 0:0.6.31-20.el7 |
avahi-autoipd Red Hat:enterprise_linux:7::computenode | All versions | 0:0.6.31-20.el7 |
avahi-compat-howl Red Hat:enterprise_linux:7::computenode | All versions | 0:0.6.31-20.el7 |
avahi-compat-howl-devel Red Hat:enterprise_linux:7::computenode | All versions | 0:0.6.31-20.el7 |
avahi-compat-libdns_sd Red Hat:enterprise_linux:7::computenode | All versions | 0:0.6.31-20.el7 |
avahi-compat-libdns_sd-devel Red Hat:enterprise_linux:7::computenode | All versions | 0:0.6.31-20.el7 |
avahi-debuginfo Red Hat:enterprise_linux:7::computenode | All versions | 0:0.6.31-20.el7 |
avahi-devel Red Hat:enterprise_linux:7::computenode | All versions | 0:0.6.31-20.el7 |
avahi-dnsconfd Red Hat:enterprise_linux:7::computenode | All versions | 0:0.6.31-20.el7 |
avahi-glib Red Hat:enterprise_linux:7::computenode | All versions | 0:0.6.31-20.el7 |
avahi-glib-devel Red Hat:enterprise_linux:7::computenode | All versions | 0:0.6.31-20.el7 |
avahi-gobject Red Hat:enterprise_linux:7::computenode | All versions | 0:0.6.31-20.el7 |
avahi-gobject-devel Red Hat:enterprise_linux:7::computenode | All versions | 0:0.6.31-20.el7 |
avahi-libs Red Hat:enterprise_linux:7::computenode | All versions | 0:0.6.31-20.el7 |
avahi-qt3 Red Hat:enterprise_linux:7::computenode | All versions | 0:0.6.31-20.el7 |
avahi-qt3-devel Red Hat:enterprise_linux:7::computenode | All versions | 0:0.6.31-20.el7 |
avahi-qt4 Red Hat:enterprise_linux:7::computenode | All versions | 0:0.6.31-20.el7 |
Products include Avahi Avahi, Canonical Ubuntu Linux.
How do I fix CVE-2017-6519?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2017-6519 being exploited?
There is no known exploitation of CVE-2017-6519 in the wild and no public exploit code.
Other vulnerabilities in Canonical Ubuntu Linux
- CVE-2021-26720 Path traversal in n/a
- CVE-2026-24401 Avahi has Uncontrolled Recursion in lookup_handle_cname function
- CVE-2025-68468 Avahi has a reachable assertion in lookup_multicast_callback
- CVE-2025-68471 Avahi has a reachable assertion in lookup_start
- CVE-2023-38469 Reachable assertion in avahi_dns_packet_append_record
Sources
Also known as ALPINE-CVE-2017-6519, AZL-6322, CVE-2018-1000845, DEBIAN-CVE-2017-6519, GHSA-6vpj-pr2c-5mm2, MGASA-2019-0081 and 2 more.