# CVE-2023-23549: DoS via long hostnames

> Privileged attackers can cause partial denial of service in the Checkmk UI by submitting excessively long hostnames.

- **Severity:** Low 2.7 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 15 Nov 2023
- **Updated:** 28 Aug 2024
- **Also known as:** GHSA-q72p-p7xm-7vmr, UBUNTU-CVE-2023-23549

## What is CVE-2023-23549?

CVE-2023-23549 is a low-severity denial of service vulnerability in Checkmk Checkmk, published on 15 Nov 2023. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

Improper Input Validation in Checkmk <2.2.0p15, <2.1.0p37, <=2.0.0p39 allows priviledged attackers to cause partial denial of service of the UI via too long hostnames.

Weakness: CWE-1284 (Improper Validation of Specified Quantity in Input)

## Which versions are affected by CVE-2023-23549?

It affects 1 product.


Products: Checkmk Checkmk.

## How do I fix CVE-2023-23549?

No fix has been published for CVE-2023-23549 yet. Limit exposure of the affected software until one is available.

## Is CVE-2023-23549 being exploited?

There is no known exploitation of CVE-2023-23549 in the wild and no public exploit code.

## Other vulnerabilities in Checkmk Checkmk

- [CVE-2025-39666](https://insights.sbomify.com/CVE-2025-39666/): omd: Local privilege escalation when executing omd commands as root (critical 9.3)
- [CVE-2024-8606](https://insights.sbomify.com/CVE-2024-8606/): Fix 2FA bypass via RestAPI (critical 9.2)
- [CVE-2022-46836](https://insights.sbomify.com/CVE-2022-46836/): PHP code injection in watolib (critical 9.1)
- [CVE-2025-32919](https://insights.sbomify.com/CVE-2025-32919/): Privilege Escalation in Windows License plugin for Checkmk Windows Agent (high 8.8)
- [CVE-2024-28827](https://insights.sbomify.com/CVE-2024-28827/): Privilege escalation in Windows agent (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-23549 and fix it if it is affected.

What it is: CVE-2023-23549 is a low-severity denial of service vulnerability in Checkmk Checkmk, published on 15 Nov 2023. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2023-23549 in the wild and no public exploit code.

Affected product: Checkmk Checkmk. 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-2023-23549/ (Markdown: https://insights.sbomify.com/CVE-2023-23549/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-23549
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-23549
- OSV: https://osv.dev/vulnerability/CVE-2023-23549

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-23549/
Summaries are generated and may contain mistakes; the official description above is the record.