---
id: "CVE-2026-123594"
page: "https://infrastack.ai/live/CVE-2026-123594"
kind: "vulnerability"
aliases: ["CVE-2026-123594"]
title: "Hickory DNS: forged NXDOMAIN answers accepted by DNSSEC validators"
severity: "medium"
cvss: 6.3
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["dns", "dnssec", "hickory-dns", "package", "rust"]
not_affected_if: ["no-dnssec-validation", "not-using-hickory"]
published_at: "2026-11-08T02:16:53+00:00"
first_seen_at: "2026-11-08T02:21:13+00:00"
updated_at: "2026-11-08T02:24:57+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-123594", "first_seen_at": "2026-11-08T02:21:13+00:00"}]
exploit_sources: []
---

# Hickory DNS: forged NXDOMAIN answers accepted by DNSSEC validators

Link for people: https://infrastack.ai/live/CVE-2026-123594 (this .md is for agents)

Hickory DNS libraries mishandle DNSSEC NSEC proofs, so a validator can accept a forged NXDOMAIN for a name that exists. An on-path attacker can flip a genuine NODATA response from NOERROR to NXDOMAIN and have it trusted.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the `hickory-proto` and `hickory-net` versions in Cargo.lock or `cargo tree` output
- Look for `hickory-proto` at or below `0.26.0-alpha.1` or `hickory-net` at `0.26.0-beta.1`

## Fix

- `hickory-proto` and `hickory-net`: move to `0.26.2` or later

## Timeline

- 2026-11-08T02:21:13+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-123594

## Documents

- [advisory] Vendor advisory: github.com https://github.com/hickory-dns/hickory-dns/security/advisories/GHSA-86vr-jm6c-7cpg
- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/hickory-dns-through-0.26.0-alpha.1-dnssec-nsec-validation-bypass-for-empty-non-terminals

## From the sources

Hickory DNS hickory-proto through 0.26.0-alpha.1 and hickory-net 0.26.0-beta.1 before 0.26.2 contain an NSEC validation flaw that returns a secure proof for NXDOMAIN responses when the covering NSEC's Next Domain Name is a strict descendant of the query name, which actually proves the name exists as an empty non-terminal. On-path attackers can flip the unsigned rcode of a genuine signed NODATA response from NOERROR to NXDOMAIN, causing validators to accept forged nonexistence of the name.

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