# CVE-2019-6474: A packet containing a malformed DUID can cause the kea-dhcp6 server to terminate

> A malformed DUID in a packet can cause the Kea DHCP6 server to fail on restart, leading to a denial of service.

- **Severity:** Medium 5.7 (`CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 16 Oct 2019
- **Updated:** 16 Sep 2024
- **Also known as:** ALPINE-CVE-2019-6474, DEBIAN-CVE-2019-6474, GHSA-qxx9-pw4x-fc72, UBUNTU-CVE-2019-6474

## What is CVE-2019-6474?

CVE-2019-6474 is a medium-severity denial of service vulnerability in ISC Kea, published on 16 Oct 2019. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

A missing check on incoming client requests can be exploited to cause a situation where the Kea server's lease storage contains leases which are rejected as invalid when the server tries to load leases from storage on restart. If the number of such leases exceeds a hard-coded limit in the Kea code, a server trying to restart will conclude that there is a problem with its lease store and give up. Versions affected: 1.4.0 to 1.5.0, 1.6.0-beta1, and 1.6.0-beta2

Weakness: CWE-772 (Missing Release of Resource after Effective Lifetime)

## Which versions are affected by CVE-2019-6474?

It affects 1 product.


Products: Isc Kea.

## How do I fix CVE-2019-6474?

Upgrade to a fixed version.

## Is CVE-2019-6474 being exploited?

There is no known exploitation of CVE-2019-6474 in the wild and no public exploit code.

## Other vulnerabilities in ISC Kea

- [CVE-2015-8373](https://insights.sbomify.com/CVE-2015-8373/): Denial of service in n/a (medium 6.8)
- [CVE-2019-6472](https://insights.sbomify.com/CVE-2019-6472/): A packet containing a malformed DUID can cause the kea-dhcp6 server to terminate (medium 6.5)
- [CVE-2018-5739](https://insights.sbomify.com/CVE-2018-5739/): Failure to release memory may exhaust system resources (medium 6.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-6474 and fix it if it is affected.

What it is: CVE-2019-6474 is a medium-severity denial of service vulnerability in ISC Kea, published on 16 Oct 2019. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2019-6474 in the wild and no public exploit code.

Affected product: ISC Kea. 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-2019-6474/ (Markdown: https://insights.sbomify.com/CVE-2019-6474/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-6474
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-6474
- OSV: https://osv.dev/vulnerability/CVE-2019-6474

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-6474/
Summaries are generated and may contain mistakes; the official description above is the record.