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TI-2026-86727 Aliases CVE-2026-123585GHSA-qw4x-w9jf-pmv6

Query amplification in Hickory DNS via irrelevant CNAME records

Priority LOW 30CWE-400Published · Updated

Key facts

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

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-400.

Summary

Hickory DNS from 0.25.0 before 0.26.2 has a flaw in its hickory-resolver component that causes unnecessary resolver work. The resolver follows irrelevant CNAME records while resolving recursive queries, which is tracked as CWE-400. A remote attacker who controls DNS responses can place CNAME records in the authority or additional sections, or outside the original query name's CNAME chain, to trigger excess queries and query amplification. The CVSS 4.0 vector shows no authentication or user interaction is needed, with impact limited to availability.

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

Description from the CNA

The hickory-resolver component of Hickory DNS 0.25.0 before 0.26.2 follows irrelevant CNAME records when resolving recursive queries, sending queries that are unnecessary to answer the original request. Attackers controlling DNS responses can include CNAME records in the authority or additional sections, or outside the original query name's CNAME chain, causing excess resolver queries and increased query amplification.

Why it matters now

EPSS 0.00304 23rd percentileScored 2026-11-08
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-dns0.25.0 to before 0.26.20.26.2Patch availableCNA
  • hickory-dns Vendorhickory-dns Affected 0.25.0 to before 0.26.2 Fixed in 0.26.2 Patch available CNA

Remediation

Upgrade hickory-dns to version 0.26.2 or later. The sources list no advisory identifier for this fix.

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 LOW 36 LOW

    Other records, highest priority first

    • TI-2026-86748 Resource exhaustion in hickory-dns recursor via glueless NS referralsPriority LOW 38
    • TI-2026-86746 Unbounded retry loop in Hickory DNS resolver enables resource exhaustionPriority LOW 38
    • TI-2026-86730 Denial of service in Hickory DNS recursive resolver via empty poolPriority LOW 38
    Show all 36 records →

Timeline

  1. 2026-11-08 Threatist record created from CVE-2026-123585
  2. 2026-11-08 Alias added: GHSA-qw4x-w9jf-pmv6
  3. 2026-11-09 Priority changed: MEDIUM → LOW

References

Advisory 1

  • TI-2025-18857 DNSSEC validation may accept broken authentication chains CVSS 4.0MEDIUM 5.7
  • TI-2026-63089 hickory-resolver before 0.26.2 DNSSEC Validation Bypass CVSS 4.0HIGH 8.7
  • 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-2026-86746 Unbounded retry loop in Hickory DNS resolver enables resource exhaustion CVSS 4.0HIGH 8.7
See all 40 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences