---
id: "CVE-2026-123574"
page: "https://infrastack.ai/live/CVE-2026-123574"
kind: "vulnerability"
aliases: ["CVE-2026-123574"]
title: "Hickory DNS zone parser panics on long token, causing denial of service"
severity: "high"
cvss: 8.7
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["dns", "hickory-dns", "package", "rust"]
not_affected_if: ["no-untrusted-zone-files", "version-0.26.2-or-later"]
published_at: "2026-11-08T02:16:50+00:00"
first_seen_at: "2026-11-08T02:21:12+00:00"
updated_at: "2026-11-08T02:22:56+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-123574", "first_seen_at": "2026-11-08T02:21:12+00:00"}]
exploit_sources: []
---

# Hickory DNS zone parser panics on long token, causing denial of service

Link for people: https://infrastack.ai/live/CVE-2026-123574 (this .md is for agents)

The zone file parser in the hickory-proto Rust crate of Hickory DNS 0.24.0 before 0.26.2 panics when a single token is 4096 bytes or longer. An attacker who can supply untrusted zone files to an application using the parser can crash it, causing denial of service.

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

## How to check

- Check whether the project depends on `hickory-proto` in its `Cargo.lock` and note the version.
- Look for any code that parses zone files supplied from outside the team (uploads, imports, API inputs).

## Fix

- `hickory-proto` `0.26.2` (the first fixed version, per the range 0.24.0 before 0.26.2)

## Timeline

- 2026-11-08T02:21:12+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-123574

## Documents

- [advisory] Vendor advisory: github.com https://github.com/hickory-dns/hickory-dns/security/advisories/GHSA-4rph-pmrw-mwpw
- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/hickory-dns-0.24.0-before-0.26.2-denial-of-service-via-zone-file-parser

## From the sources

The zone file parser in the hickory-proto crate of Hickory DNS 0.24.0 before 0.26.2 panics when a single token in a zone file is 4096 bytes or longer. Attackers who can supply untrusted zone files to an application using the parser can trigger the panic to cause a denial of service.

---

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