# CVE-2016-5426: Denial of service in n/a

> Remote attackers can cause denial of service via high CPU consumption by sending a long query name to PowerDNS Authoritative Server.

- **Severity:** High 7.5 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 21 Sep 2016
- **Updated:** 6 Aug 2024
- **Also known as:** DEBIAN-CVE-2016-5426, GHSA-ghrw-639j-38vq

## What is CVE-2016-5426?

CVE-2016-5426 is a high-severity denial of service vulnerability in n/a, published on 21 Sep 2016. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

PowerDNS (aka pdns) Authoritative Server before 3.4.10 allows remote attackers to cause a denial of service (backend CPU consumption) via a long qname.

Weakness: CWE-399

## Which versions are affected by CVE-2016-5426?

It affects 1 product.


Products: Powerdns Authoritative.

## How do I fix CVE-2016-5426?

Upgrade to a fixed version.

## Is CVE-2016-5426 being exploited?

There is no known exploitation of CVE-2016-5426 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2020-24698](https://insights.sbomify.com/CVE-2020-24698/): Use after free in n/a (critical 9.8)
- [CVE-2020-24696](https://insights.sbomify.com/CVE-2020-24696/): Race condition in n/a (high 8.1)
- [CVE-2015-5470](https://insights.sbomify.com/CVE-2015-5470/): Denial of service in n/a (high 7.8)
- [CVE-2026-42001](https://insights.sbomify.com/CVE-2026-42001/): Insufficient Validation of Autoprimary SOA Queries (high 7.5)
- [CVE-2020-24697](https://insights.sbomify.com/CVE-2020-24697/): Denial of service in n/a (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2016-5426 and fix it if it is affected.

What it is: CVE-2016-5426 is a high-severity denial of service vulnerability in n/a, published on 21 Sep 2016. 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-2016-5426 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-2016-5426/ (Markdown: https://insights.sbomify.com/CVE-2016-5426/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2016-5426
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2016-5426
- OSV: https://osv.dev/vulnerability/CVE-2016-5426

---
From sbomify Insights: https://insights.sbomify.com/CVE-2016-5426/
Summaries are generated and may contain mistakes; the official description above is the record.