# CVE-2023-50387: Denial of service in n/a

> Remote attackers can cause CPU exhaustion in DNS resolvers by sending crafted DNSSEC responses, leading to denial of service.

- **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:** Yes
- **Published:** 14 Feb 2024
- **Updated:** 4 Nov 2025
- **Also known as:** ALPINE-CVE-2023-50387, AZL-34350, AZL-34419, AZL-34440, AZL-34559, AZL-35328, BELL-CVE-2023-50387, CLEANSTART-2026-LD91251, CLSA-2024-1722529717, DEBIAN-CVE-2023-50387, GHSA-8459-gg55-8qjj, UBUNTU-CVE-2023-50387, openSUSE-SU-2024:13680-1, openSUSE-SU-2024:13707-1

## What is CVE-2023-50387?

CVE-2023-50387 is a high-severity denial of service vulnerability in Fedoraproject Fedora, published on 14 Feb 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Certain DNSSEC aspects of the DNS protocol (in RFC 4033, 4034, 4035, 6840, and related RFCs) allow remote attackers to cause a denial of service (CPU consumption) via one or more DNSSEC responses, aka the "KeyTrap" issue. One of the concerns is that, when there is a zone with many DNSKEY and RRSIG records, the protocol specification implies that an algorithm must evaluate all combinations of DNSKEY and RRSIG records.

Weakness: CWE-770 (Allocation of Resources Without Limits or Throttling)

## Which versions are affected by CVE-2023-50387?

It affects 13 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `dnsmasq` | openSUSE:Tumbleweed | All versions | 2.90-1.1 |
| `pdns-recursor` | openSUSE:Tumbleweed | All versions | 5.0.2-1.1 |

Products: Fedoraproject Fedora, Isc Bind, Microsoft Windows Server 2008, Microsoft Windows Server 2012, Microsoft Windows Server 2016, Microsoft Windows Server 2019, Microsoft Windows Server 2022, Microsoft Windows Server 2022 23h2, Nic Knot Resolver, Nlnetlabs Unbound, Powerdns Recursor, Redhat Enterprise Linux, Thekelleys Dnsmasq.

## How do I fix CVE-2023-50387?

Apply the vendor's patch.

## Is CVE-2023-50387 being exploited?

There is no known exploitation of CVE-2023-50387 in the wild and no public exploit code.

Public exploit code:

- KeyTrap (DNSSEC) (github_poc): https://github.com/knqyf263/CVE-2023-50387
- In this repository you can find the files used to try to produce a POC for the CVE-2023-50387 (github_poc): https://github.com/Meirelez/SSR-DNSSEC
- https://github.com/Pablodiz/CVE-2023-50387 (github_poc): https://github.com/Pablodiz/CVE-2023-50387

## Other vulnerabilities in Fedoraproject Fedora

- [CVE-2024-4577](https://insights.sbomify.com/CVE-2024-4577/): PHP-CGI OS Command Injection (critical 9.8, exploited in the wild)
- [CVE-2021-39226](https://insights.sbomify.com/CVE-2021-39226/): Grafana Authentication Bypass (critical 9.8, exploited in the wild)
- [CVE-2019-5544](https://insights.sbomify.com/CVE-2019-5544/): VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2024-4947](https://insights.sbomify.com/CVE-2024-4947/): Google Chromium V8 Type Confusion (critical 9.6, exploited in the wild)
- [CVE-2024-4671](https://insights.sbomify.com/CVE-2024-4671/): Google Chromium Visuals Use-After-Free (critical 9.6, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-50387 and fix it if it is affected.

What it is: CVE-2023-50387 is a high-severity denial of service vulnerability in Fedoraproject Fedora, 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-2023-50387 in the wild and no public exploit code.

Affected product: Fedoraproject Fedora. 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-2023-50387/ (Markdown: https://insights.sbomify.com/CVE-2023-50387/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-50387
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-50387
- OSV: https://osv.dev/vulnerability/CVE-2023-50387

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-50387/
Summaries are generated and may contain mistakes; the official description above is the record.