# CVE-2023-50868: Denial of service in n/a

> Remote attackers can cause denial of service via CPU exhaustion in DNSSEC NSEC3 processing, affecting DNS resolvers.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 14 Feb 2024
- **Updated:** 4 Nov 2025
- **Also known as:** ALPINE-CVE-2023-50868, AZL-34441, AZL-35329, BELL-CVE-2023-50868, CLEANSTART-2026-RU38296, CLSA-2024-1729513208, CLSA-2025-1756230743, CLSA-2025-1765282338, DEBIAN-CVE-2023-50868, GHSA-pv4h-p8jr-6cv2, UBUNTU-CVE-2023-50868

## What is CVE-2023-50868?

CVE-2023-50868 is a high-severity denial of service vulnerability in Debian Debian Linux, published on 14 Feb 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The Closest Encloser Proof aspect of the DNS protocol (in RFC 5155 when RFC 9276 guidance is skipped) allows remote attackers to cause a denial of service (CPU consumption for SHA-1 computations) via DNSSEC responses in a random subdomain attack, aka the "NSEC3" issue. The RFC 5155 specification implies that an algorithm must perform thousands of iterations of a hash function in certain situations.

Weakness: CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2023-50868?

It affects 8 products.


Products: Debian Debian Linux, Fedoraproject Fedora, Isc Bind, Netapp Active Iq Unified Manager, Netapp Bootstrap Os, Netapp Hci Baseboard Management Controller, Powerdns Recursor, Redhat Enterprise Linux.

## How do I fix CVE-2023-50868?

Apply the vendor's patch.

## Is CVE-2023-50868 being exploited?

There is no known exploitation of CVE-2023-50868 in the wild and no public exploit code.

Public exploit code:

- This project generates DNS zonefiles with custom NSEC3 parameters to reproduce and evaluate the attacks in CVE-2023-50868. (github_poc): https://github.com/Goethe-Universitat-Cybersecurity/NSEC3-Encloser-Attack

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-50868 and fix it if it is affected.

What it is: CVE-2023-50868 is a high-severity denial of service vulnerability in Debian Debian Linux, published on 14 Feb 2024. 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-2023-50868 in the wild and no public exploit code.

Affected product: Debian Debian Linux. 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-2023-50868/ (Markdown: https://insights.sbomify.com/CVE-2023-50868/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-50868
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-50868
- OSV: https://osv.dev/vulnerability/CVE-2023-50868

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-50868/
Summaries are generated and may contain mistakes; the official description above is the record.