# CVE-2026-12244: nsd: If NSD is configured as secondary for a zone, the primary of that zone can crash NSD with an AXFR containing a DNS me...

CVE-2026-12244 is fixed in nsd on 1 platform, first by nsd 4.14.0-1ubuntu0.1~esm1, released June 24, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-12244
- Priority: High
- CVSS: 8.8 (high)
- EPSS: 0.0049
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jun 24, 2026

## Description

If NSD is configured as secondary for a zone, the primary of that zone can crash NSD with an AXFR containing a DNS message with a special crafted SVCB RR with an rdata size of 65512, that let's an (uint16_t) variable that is used to allocate space needed for the RR wrap (because total size > 65535), causing a heap overflow. The attacker can perform a controlled (RCE class) head write of up to 65509 bytes

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | nsd Debian 14 | 4.14.3-1 | [DEBIAN-CVE-2026-12244](https://patchblox.com/security/data/fix/linux/debian-cve-2026-12244.md) | Jun 28, 2026 |
| Linux | nsd Ubuntu 26.04.1 LTS (resolute) | 4.14.0-1ubuntu0.1~esm1 | [nsd 4.14.0-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-nsd-4.14.0-1ubuntu0.1-esm1.md) | Jun 24, 2026 |
| Linux | nsd opensuse-leap 16.0 | 4.14.3-bp160.1.1 | [OPENSUSE-SU-2026:21502-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21502-1.md) | Jul 29, 2026 |

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Data as of 2026-11-09T01:18:40Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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