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TI-2026-86728 Aliases CVE-2026-123586GHSA-fcx4-92qj-2p7q

Query amplification in Hickory DNS recursive resolver

Priority MEDIUM 53CWE-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 · High
Fix status
Fixed

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

Summary

Hickory DNS versions from 0 before 0.26.2 are affected, including 0.25.0-alpha.3 through 0.25.2. The recursive resolver mishandles cyclic sibling name server referrals that lack glue records (CWE-400). A remote attacker with no privileges and no user interaction who controls two zones whose name servers reference each other can make the resolver send many upstream queries, which zero-TTL NS records amplify, with high availability impact.

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

Description from the CNA

Hickory DNS 0.25.0-alpha.3 through 0.25.2 contains a query amplification vulnerability in its recursive resolver, which mishandles cyclic sibling name server referrals that lack glue records. Attackers controlling two zones whose name servers reference each other without glue records can make the recursor loop, sending many upstream queries, amplified further by zero-TTL NS records.

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-dns0.25.0-alpha.3 – 0.25.2—No fix listedCNA
hickory-dnshickory-dnsbefore 0.26.20.26.2Patch availableCNA
  • hickory-dns Vendorhickory-dns Affected 0.25.0-alpha.3 – 0.25.2 Fixed in — No fix listed CNA
  • hickory-dns Vendorhickory-dns Affected before 0.26.2 Fixed in 0.26.2 Patch available CNA

Remediation

Upgrade hickory-dns to version 0.26.2, which fixes the flaw. The sources list no fixed version for the 0.25.0-alpha.3 through 0.25.2 range.

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
    Show all 36 records →

Timeline

  1. 2026-11-08 Threatist record created from CVE-2026-123586
  2. 2026-11-08 Alias added: GHSA-fcx4-92qj-2p7q

References

Advisory 1

  • 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

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