---
id: "CVE-2026-123606"
page: "https://infrastack.ai/live/CVE-2026-123606"
kind: "vulnerability"
aliases: ["CVE-2026-123606"]
title: "Hickory DNS recursor: unbounded NS lookups let attackers amplify traffic"
severity: "high"
cvss: 8.7
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["dns", "hickory-dns", "package", "rust", "self-hosted"]
not_affected_if: ["no-hickory-dependency", "stub-resolver-only", "trusted-upstream"]
published_at: "2026-11-08T02:16:55+00:00"
first_seen_at: "2026-11-08T02:21:14+00:00"
updated_at: "2026-11-08T02:22:47+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-123606", "first_seen_at": "2026-11-08T02:21:14+00:00"}]
exploit_sources: []
---

# Hickory DNS recursor: unbounded NS lookups let attackers amplify traffic

Link for people: https://infrastack.ai/live/CVE-2026-123606 (this .md is for agents)

The hickory-recursor and hickory-resolver Rust DNS libraries look up every out-of-bailiwick name server in a referral without a work limit. A remote attacker who serves crafted referrals can force many A and AAAA lookups, amplifying traffic against other servers or exhausting the recursor's resources.

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

## How to check

- Check the hickory-recursor version in Cargo.lock, for example with `grep -A1 'name = "hickory-recursor"' Cargo.lock`
- Check the hickory-resolver version in Cargo.lock, for example with `grep -A1 'name = "hickory-resolver"' Cargo.lock`
- Look for hickory-recursor 0.25.0-alpha.3 through 0.25.2, or hickory-resolver 0.26.0-alpha.1 before 0.26.2

## Fix

- hickory-resolver: `0.26.2` or later (from the advisory range, fixed in 0.26.2)
- hickory-recursor: the sources do not name a fixed version for the 0.25 line

## Timeline

- 2026-11-08T02:21:14+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-123606

## Documents

- [advisory] Vendor advisory: github.com https://github.com/hickory-dns/hickory-dns/security/advisories/GHSA-6h5c-jjg5-wj59
- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/hickory-dns-recursor-0.25.0-alpha.3-through-0.25.2-glueless-ns-referral-amplification

## From the sources

The hickory-dns recursor in hickory-recursor 0.25.0-alpha.3 through 0.25.2 and hickory-resolver 0.26.0-alpha.1 before 0.26.2 iterates every out-of-bailiwick NS target lacking glue in a referral without any per-query work budget. Remote attackers can serve such referrals to force A and AAAA lookups per target, amplifying traffic against remote servers or exhausting recursor resources.

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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_