# CVE-2026-40719: Denial of service in MaraDNS

> Attackers can exhaust connection slots in MaraDNS by configuring a zone with an unresolvable authoritative nameserver address.

- **Severity:** High 7.5 (`CVSS:3.1/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:** No
- **Published:** 15 Apr 2026
- **Updated:** 15 Apr 2026
- **Also known as:** DEBIAN-CVE-2026-40719, GHSA-8wr7-69hr-44pw, GHSA-cfc6-vhrv-62cj, UBUNTU-CVE-2026-40719

## What is CVE-2026-40719?

CVE-2026-40719 is a high-severity denial of service vulnerability in MaraDNS, published on 15 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Deadwood in MaraDNS 3.5.0036 allows attackers to exhaust connection slots via a zone whose authoritative nameserver address cannot be resolved.

Weakness: CWE-670 (Always-Incorrect Control Flow Implementation)

## Which versions are affected by CVE-2026-40719?


## How do I fix CVE-2026-40719?

No fix has been published for CVE-2026-40719 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-40719 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-40719 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-40719 and fix it if it is affected.

What it is: CVE-2026-40719 is a high-severity denial of service vulnerability in MaraDNS, published on 15 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-40719 exists.

Affected product: MaraDNS. 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-2026-40719/ (Markdown: https://insights.sbomify.com/CVE-2026-40719/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-40719
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-40719
- OSV: https://osv.dev/vulnerability/CVE-2026-40719

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-40719/
Summaries are generated and may contain mistakes; the official description above is the record.