---
id: "CVE-2026-123601"
page: "https://infrastack.ai/live/CVE-2026-123601"
kind: "vulnerability"
aliases: ["CVE-2026-123601"]
title: "Hickory DNS: inverted NSEC3 check lets forged responses deny real names"
severity: "high"
cvss: 8.3
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["dns-resolver", "dnssec", "hickory-dns", "package", "rust"]
not_affected_if: ["does-not-use-hickory", "no-dnssec-validation"]
published_at: "2026-11-08T02:16:54+00:00"
first_seen_at: "2026-11-08T02:21:14+00:00"
updated_at: "2026-11-08T02:23:14+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-123601", "first_seen_at": "2026-11-08T02:21:14+00:00"}]
exploit_sources: []
---

# Hickory DNS: inverted NSEC3 check lets forged responses deny real names

Link for people: https://infrastack.ai/live/CVE-2026-123601 (this .md is for agents)

Hickory DNS libraries (hickory-proto and hickory-net) invert a comparison in NSEC3 wrap-around handling, so the last NSEC3 record in a zone covers almost every hash. An attacker who can inject DNS responses can replay that record and its signature to produce DNSSEC-validated negative answers that deny names that exist.

_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 your `Cargo.lock` or dependency tree.
- Flag `hickory-proto` 0.25.0 through 0.26.0-alpha.1, and `hickory-net` 0.26.0-beta.1, as affected.

## Fix

- `hickory-net` and `hickory-proto`: move to `0.26.2` or later (per the NVD summary, fixed before 0.26.2).

## Timeline

- 2026-11-08T02:21:14+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-123601

## Documents

- [advisory] Vendor advisory: github.com https://github.com/hickory-dns/hickory-dns/security/advisories/GHSA-588m-chg6-8jqj
- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/hickory-dns-0.26.0-beta.1-before-0.26.2-nsec3-proof-of-nonexistence-forgery

## From the sources

Hickory DNS hickory-proto 0.25.0 through 0.26.0-alpha.1 and hickory-net 0.26.0-beta.1 before 0.26.2 invert the relational operators in the wrap-around branch of find_covering_record() in nsec3.rs, so the last NSEC3 record in a zone's hash ring covers every hash except its owner. Attackers able to inject DNS responses can replay that NSEC3 record and its RRSIG to forge DNSSEC-validated negative responses denying legitimate names.

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_Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai_