# CVE-2006-6870: Denial of service in n/a

> Remote attackers can cause a denial of service in Avahi via a crafted compressed DNS response triggering an infinite loop.

- **Severity:** Medium 5.0 (`AV:N/AC:L/Au:N/C:N/I:N/A:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 5 Jan 2007
- **Updated:** 7 Aug 2024
- **Also known as:** DEBIAN-CVE-2006-6870, GHSA-mc78-8grw-5ghv

## What is CVE-2006-6870?

CVE-2006-6870 is a medium-severity denial of service vulnerability in n/a, published on 5 Jan 2007. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The consume_labels function in avahi-core/dns.c in Avahi before 0.6.16 allows remote attackers to cause a denial of service (infinite loop) via a crafted compressed DNS response with a label that points to itself.

## Which versions are affected by CVE-2006-6870?

It affects 1 product.


Products: Avahi Avahi.

## How do I fix CVE-2006-6870?

Upgrade to a fixed version.

## Is CVE-2006-6870 being exploited?

There is no known exploitation of CVE-2006-6870 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2017-6519](https://insights.sbomify.com/CVE-2017-6519/): Denial of service in n/a (critical 9.1)
- [CVE-2021-26720](https://insights.sbomify.com/CVE-2021-26720/): Path traversal in n/a (high 7.8)
- [CVE-2026-24401](https://insights.sbomify.com/CVE-2026-24401/): Avahi has Uncontrolled Recursion in lookup_handle_cname function (medium 6.5)
- [CVE-2025-68468](https://insights.sbomify.com/CVE-2025-68468/): Avahi has a reachable assertion in lookup_multicast_callback (medium 6.5)
- [CVE-2025-68471](https://insights.sbomify.com/CVE-2025-68471/): Avahi has a reachable assertion in lookup_start (medium 6.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2006-6870 and fix it if it is affected.

What it is: CVE-2006-6870 is a medium-severity denial of service vulnerability in n/a, published on 5 Jan 2007. 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-2006-6870 in the wild and no public exploit code.

Affected product: n/a. 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-2006-6870/ (Markdown: https://insights.sbomify.com/CVE-2006-6870/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2006-6870
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2006-6870
- OSV: https://osv.dev/vulnerability/CVE-2006-6870

---
From sbomify Insights: https://insights.sbomify.com/CVE-2006-6870/
Summaries are generated and may contain mistakes; the official description above is the record.