# CVE-2025-30193: Denial of service via crafted TCP exchange

> An attacker can cause a denial of service by exhausting the stack via crafted TCP exchanges when unlimited queries are allowed on a single connection.

- **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:** 20 May 2025
- **Updated:** 20 May 2025
- **Also known as:** DEBIAN-CVE-2025-30193, GHSA-4q3h-v92p-gchj, SUSE-SU-2025:01745-1, SUSE-SU-2025:01792-1, UBUNTU-CVE-2025-30193

## What is CVE-2025-30193?

CVE-2025-30193 is a high-severity denial of service vulnerability in PowerDNS DNSdist, published on 20 May 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In some circumstances, when DNSdist is configured to allow an unlimited number of queries on a single, incoming TCP connection from a client, an attacker can cause a denial of service by crafting a TCP exchange that triggers an exhaustion of the stack and a crash of DNSdist, causing a denial of service.

The remedy is: upgrade to the patched 1.9.10 version.

A workaround is to restrict the maximum number of queries on incoming TCP connections to a safe value, like 50, via the setMaxTCPQueriesPerConnection setting.

We would like to thank Renaud Allard for bringing this issue to our attention.

Weakness: CWE-674 (Uncontrolled Recursion)

## Which versions are affected by CVE-2025-30193?


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `dnsdist` | SUSE:Enterprise Storage 7.1 | All versions | 1.8.0-150100.3.8.1 |
| `dnsdist` | SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | All versions | 1.8.0-150400.9.6.1 |
| `dnsdist` | SUSE:Linux Enterprise High Performance Computing 15 SP4-LTSS | All versions | 1.8.0-150400.9.6.1 |
| `dnsdist` | SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS | All versions | 1.8.0-150400.9.6.1 |
| `dnsdist` | SUSE:Linux Enterprise High Performance Computing 15 SP5-LTSS | All versions | 1.8.0-150400.9.6.1 |
| `dnsdist` | SUSE:Linux Enterprise Module for Basesystem 15 SP6 | All versions | 1.8.0-150400.9.6.1 |
| `dnsdist` | SUSE:Linux Enterprise Server 15 SP3-LTSS | All versions | 1.8.0-150100.3.8.1 |
| `dnsdist` | SUSE:Linux Enterprise Server 15 SP4-LTSS | All versions | 1.8.0-150400.9.6.1 |
| `dnsdist` | SUSE:Linux Enterprise Server 15 SP5-LTSS | All versions | 1.8.0-150400.9.6.1 |
| `dnsdist` | SUSE:Linux Enterprise Server for SAP Applications 15 SP4 | All versions | 1.8.0-150400.9.6.1 |
| `dnsdist` | SUSE:Linux Enterprise Server for SAP Applications 15 SP5 | All versions | 1.8.0-150400.9.6.1 |
| `dnsdist` | SUSE:Manager Proxy 4.3 | All versions | 1.8.0-150400.9.6.1 |
| `dnsdist` | SUSE:Manager Server 4.3 | All versions | 1.8.0-150400.9.6.1 |
| `dnsdist` | openSUSE:Leap 15.6 | All versions | 1.8.0-150400.9.6.1 |

## How do I fix CVE-2025-30193?

Upgrade to a fixed version.

## Is CVE-2025-30193 being exploited?

There is no known exploitation of CVE-2025-30193 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-30193 and fix it if it is affected.

What it is: CVE-2025-30193 is a high-severity denial of service vulnerability in PowerDNS DNSdist, published on 20 May 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-2025-30193 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-2025-30193/ (Markdown: https://insights.sbomify.com/CVE-2025-30193/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-30193
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-30193
- OSV: https://osv.dev/vulnerability/CVE-2025-30193

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-30193/
Summaries are generated and may contain mistakes; the official description above is the record.