---
id: "CVE-2026-123571"
page: "https://infrastack.ai/live/CVE-2026-123571"
kind: "vulnerability"
aliases: ["CVE-2026-123571"]
title: "Hickory DNS: malformed TSIG record crashes the server with a panic"
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-tsig-handling", "versions-outside-range"]
published_at: "2026-11-08T02:16:49+00:00"
first_seen_at: "2026-11-08T02:21:12+00:00"
updated_at: "2026-11-08T02:22:59+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-123571", "first_seen_at": "2026-11-08T02:21:12+00:00"}]
exploit_sources: []
---

# Hickory DNS: malformed TSIG record crashes the server with a panic

Link for people: https://infrastack.ai/live/CVE-2026-123571 (this .md is for agents)

Hickory DNS versions from 0.26.0 before 0.26.2 have an integer underflow in how they decode TSIG records. A remote attacker can send a crafted DNS message that makes the server panic, causing denial of service.

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

## Fix

- Hickory DNS: move to `0.26.2` or later

## Timeline

- 2026-11-08T02:21:12+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-123571

## Documents

- [advisory] Vendor advisory: github.com https://github.com/hickory-dns/hickory-dns/security/advisories/GHSA-x962-5xwx-fr8x
- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/hickory-dns-from-0.26.0-before-0.26.2-panic-via-tsig-rdata-decoding

## From the sources

Hickory DNS from 0.26.0 before 0.26.2 contains an integer underflow vulnerability in TSIG RDATA decoding that allows remote attackers to trigger a panic via malformed records. Attackers can send a crafted TSIG record in DNS wire format to cause unchecked subtraction underflow, crashing builds with overflow checks enabled and causing denial of service.

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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_