# CVE-2023-26249: knot-resolver: Knot Resolver before 5.6.0 enables attackers to consume its resources, launching amplification attacks and potentiall...

CVE-2023-26249 is fixed in knot-resolver on 1 platform, first by DEBIAN-CVE-2023-26249, released February 21, 2023. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2023-26249
- Priority: High
- CVSS: 7.5 (high)
- EPSS: 0.0071
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Feb 21, 2023

## Description

Knot Resolver before 5.6.0 enables attackers to consume its resources, launching amplification attacks and potentially causing a denial of service. Specifically, a single client query may lead to a hundred TCP connection attempts if a DNS server closes connections without providing a response.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | knot-resolver Debian 12.15 (bookworm) | 5.6.0-1 | [DEBIAN-CVE-2023-26249](https://patchblox.com/security/data/fix/linux/debian-cve-2023-26249.md) | Feb 21, 2023 |
| Linux | knot-resolver Debian 13.5 (trixie) | 5.6.0-1 | [DEBIAN-CVE-2023-26249](https://patchblox.com/security/data/fix/linux/debian-cve-2023-26249.md) | Feb 21, 2023 |
| Linux | knot-resolver Debian 14 | 5.6.0-1 | [DEBIAN-CVE-2023-26249](https://patchblox.com/security/data/fix/linux/debian-cve-2023-26249.md) | Feb 21, 2023 |

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Data as of 2026-11-08T13:06:02Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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