---
id: CVE-2026-123595
title: >-
  Hickory DNS through 0.26.0-alpha.1 DNSSEC Validation Bypass via
  Ancestor-Delegation NSEC3
summary: >-
  Hickory DNS hickory-proto 0.25 through 0.26.0-alpha.1 and hickory-net
  0.26.0-beta.1 before 0.26.2 contain a DNSSEC validation flaw in the validating
  recursor's NSEC3 handler, which matches the closest encloser by hash alone
  without check…
severity: high
cvss: 8.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
cwe:
  - CWE-345
vendor: hickory-dns
product: hickory-dns
affected:
  - hickory-dns >= 0.25 <= 0.26.0-alpha.1
  - hickory-dns >= 0.26.0-beta.1 < 0.26.2
published: '2026-11-08'
updated: '2026-11-08'
sourceUpdated: '2026-11-08T01:38:25.078Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-123595'
references:
  - url: >-
      https://github.com/hickory-dns/hickory-dns/security/advisories/GHSA-624w-vvww-xvpw
    label: GitHub Security Advisory (GHSA-624w-vvww-xvpw)
  - url: >-
      https://www.vulncheck.com/advisories/hickory-dns-through-0.26.0-alpha.1-dnssec-validation-bypass-via-ancestor-delegation-nsec3
    label: >-
      VulnCheck Advisory: Hickory DNS through 0.26.0-alpha.1 DNSSEC Validation
      Bypass via Ancestor-Delegation NSEC3
tags:
  - cve.org
ingestedAt: '2026-11-08T02:43:18.644Z'
---

## Overview

Hickory DNS hickory-proto 0.25 through 0.26.0-alpha.1 and hickory-net 0.26.0-beta.1 before 0.26.2 contain a DNSSEC validation flaw in the validating recursor's NSEC3 handler, which matches the closest encloser by hash alone without checking the type bitmap and so accepts parent-side ancestor-delegation NSEC3 records as proof of nonexistence. An attacker who delivers one response built from genuinely signed parent NSEC3 records can cause NXDOMAIN or NODATA to be cached with AD=1, denying resolution of existing names at and below the zone cut.

## Affected

- `hickory-dns >= 0.25 <= 0.26.0-alpha.1`
- `hickory-dns >= 0.26.0-beta.1 < 0.26.2`

## Remediation

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