# CVE-2025-30193: dnsdist: In some circumstances, when DNSdist is configured to allow an unlimited number of queries on a single, incoming TCP c...

CVE-2025-30193 is fixed in dnsdist on 1 platform, first by dnsdist 1.6.1-1ubuntu0.1~esm2, released May 20, 2025. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2025-30193
- Priority: High
- CVSS: 7.5 (high)
- EPSS: 0.0062
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: May 20, 2025

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | dnsdist Debian 13.5 (trixie) | 1.9.10-1 | [DEBIAN-CVE-2025-30193](https://patchblox.com/security/data/fix/linux/debian-cve-2025-30193.md) | May 20, 2025 |
| Linux | dnsdist Debian 14 | 1.9.10-1 | [DEBIAN-CVE-2025-30193](https://patchblox.com/security/data/fix/linux/debian-cve-2025-30193.md) | May 20, 2025 |
| Linux | dnsdist Ubuntu 22.04.1 LTS (jammy) | 1.6.1-1ubuntu0.1~esm2 | [dnsdist 1.6.1-1ubuntu0.1~esm2](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-dnsdist-1.6.1-1ubuntu0.1-esm2.md) | May 20, 2025 |
| Linux | dnsdist Ubuntu 24.04.5 LTS (noble) | 1.8.3-2ubuntu0.1~esm1 | [dnsdist 1.8.3-2ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-dnsdist-1.8.3-2ubuntu0.1-esm1.md) | Aug 13, 2025 |
| Linux | dnsdist opensuse-leap 15.6 | 1.8.0-150400.9.6.1 | [SUSE-SU-2025:01745-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-01745-1.md) | May 29, 2025 |
| Linux | dnsdist sles 15.6 | 1.8.0-150400.9.6.1 | [SUSE-SU-2025:01745-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-01745-1.md) | May 29, 2025 |
| Linux | dnsdist sles 15.7 | 1.9.10-150700.3.3.1 | [SUSE-SU-2025:01743-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-01743-1.md) | May 29, 2025 |

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Data as of 2026-11-08T19:12:23Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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