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Denial of service in Hickory DNS zone file parser via long tokens

Priority MEDIUM 53CWE-20Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
—
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

The zone file parser in the hickory-proto crate of Hickory DNS from 0.24.0 before 0.26.2 panics when a single token in a zone file is 4096 bytes or longer. A remote attacker without privileges who can supply untrusted zone files to an application using the parser can crash it, causing a denial of service. The flaw is an improper input validation issue (CWE-20).

Written with Claude Haiku 5.5 from the sources below · 2026-11-08

Description from the CNA

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.

Why it matters now

Fix Fixed hickory-dns (hickory-dns): 0.26.2

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
hickory-dnshickory-dns0.24.0 to before 0.26.20.26.2Patch availableCNA
  • hickory-dns Vendorhickory-dns Affected 0.24.0 to before 0.26.2 Fixed in 0.26.2 Patch available CNA

Remediation

Update hickory-dns to version 0.26.2.

Written with Claude Haiku 5.5 from the sources below · 2026-11-08

  • Fix · CNA hickory-dns (hickory-dns) Fixed in 0.26.2

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    hickory-dns 0.26.2

    36 records Highest priority Priority MEDIUM 36 MEDIUM

    Other records, highest priority first

    • TI-2026-86729 DNSSEC nonexistence forgery in Hickory DNS via wraparound NSECPriority MEDIUM 54
    • TI-2026-86748 Resource exhaustion in hickory-dns recursor via glueless NS referralsPriority MEDIUM 53
    • TI-2026-86747 DNSSEC validation bypass in Hickory DNS via RRSIG signer namePriority MEDIUM 53

Timeline

  1. 2026-11-08 Threatist record created from CVE-2026-123574
  2. 2026-11-08 Alias added: GHSA-29xw-595w-jfj7

References

  • TI-2025-18857 DNSSEC validation may accept broken authentication chains CVSS 4.0MEDIUM 5.7
  • TI-2026-86729 DNSSEC nonexistence forgery in Hickory DNS via wraparound NSEC CVSS 4.0HIGH 8.9
  • TI-2026-86750 CPU exhaustion in Hickory DNS hickory-proto via BinEncoder name compression CVSS 4.0HIGH 8.7
  • TI-2026-86749 Hickory DNS NSEC3 validation loop enables denial of service CVSS 4.0HIGH 8.7
  • TI-2026-86748 Resource exhaustion in hickory-dns recursor via glueless NS referrals CVSS 4.0HIGH 8.7
  • TI-2026-86747 DNSSEC validation bypass in Hickory DNS via RRSIG signer name CVSS 4.0HIGH 8.7
See all 40 →

Sources