---
id: CVE-2026-123591
title: >-
  Hickory DNS 0.26.0-beta.1 before 0.26.2 DNSSEC Validation Bypass via Missing
  RFC 6840 Checks
summary: >-
  Hickory DNS hickory-net 0.26.0-beta.1 before 0.26.2 and hickory-proto through
  0.26.0-alpha.1 fail to verify, per RFC 6840 §4.4, that an NSEC or NSEC3 record
  denying a DS RRset also proves the delegation's NS record exists. Attackers
  can …
severity: medium
cvss: 5.9
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N'
cvssSource: cna
cwe:
  - CWE-345
vendor: hickory-dns
product: hickory-dns
affected:
  - hickory-dns >= 0.26.0-beta.1 < 0.26.2
  - hickory-dns <= 0.26.0-alpha.1
published: '2026-11-08'
updated: '2026-11-08'
sourceUpdated: '2026-11-08T01:38:22.338Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-123591'
references:
  - url: >-
      https://github.com/hickory-dns/hickory-dns/security/advisories/GHSA-7php-9j59-g3ch
    label: GitHub Security Advisory (GHSA-7php-9j59-g3ch)
  - url: >-
      https://www.vulncheck.com/advisories/hickory-dns-0.26.0-beta.1-before-0.26.2-dnssec-validation-bypass-via-missing-rfc-6840-checks
    label: >-
      VulnCheck Advisory: Hickory DNS 0.26.0-beta.1 before 0.26.2 DNSSEC
      Validation Bypass via Missing RFC 6840 Checks
tags:
  - cve.org
ingestedAt: '2026-11-08T02:43:18.646Z'
---

## Overview

Hickory DNS hickory-net 0.26.0-beta.1 before 0.26.2 and hickory-proto through 0.26.0-alpha.1 fail to verify, per RFC 6840 §4.4, that an NSEC or NSEC3 record denying a DS RRset also proves the delegation's NS record exists. Attackers can reuse child-side NSEC or NSEC3 records to fake an insecure delegation and forge child-zone records.

## Affected

- `hickory-dns >= 0.26.0-beta.1 < 0.26.2`
- `hickory-dns <= 0.26.0-alpha.1`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.