# CVE-2025-30194: Denial of service via crafted DoH exchange

> An attacker can cause a denial of service in DNSdist by triggering a double-free crash via a crafted DoH exchange when using the nghttp2 provider.

- **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:** 29 Apr 2025
- **Updated:** 20 Jun 2025
- **Also known as:** DEBIAN-CVE-2025-30194, GHSA-487w-xx5j-gqwc, openSUSE-SU-2025:15157-1

## What is CVE-2025-30194?

CVE-2025-30194 is a high-severity use after free vulnerability in PowerDNS DNSdist, published on 29 Apr 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

When DNSdist is configured to provide DoH via the nghttp2 provider, an attacker can cause a denial of service by crafting a DoH exchange that triggers an illegal memory access (double-free) and crash of DNSdist, causing a denial of service.

The remedy is: upgrade to the patched 1.9.9 version.

A workaround is to temporarily switch to the h2o provider until DNSdist has been upgraded to a fixed version.

We would like to thank Charles Howes for bringing this issue to our attention.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2025-30194?


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `dnsdist` | openSUSE:Tumbleweed | All versions | 1.9.10-2.1 |

## How do I fix CVE-2025-30194?

Upgrade to a fixed version.

## Is CVE-2025-30194 being exploited?

There is no known exploitation of CVE-2025-30194 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-30194 and fix it if it is affected.

What it is: CVE-2025-30194 is a high-severity use after free vulnerability in PowerDNS DNSdist, published on 29 Apr 2025. 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-2025-30194 in the wild and no public exploit code.

Affected product: PowerDNS DNSdist. 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-2025-30194/ (Markdown: https://insights.sbomify.com/CVE-2025-30194/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-30194
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-30194
- OSV: https://osv.dev/vulnerability/CVE-2025-30194

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-30194/
Summaries are generated and may contain mistakes; the official description above is the record.