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TI-2026-86748 Aliases CVE-2026-123606GHSA-5p73-2jm7-2cmq

Resource exhaustion in hickory-dns recursor via glueless NS referrals

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-recursor versions 0.25.0-alpha.3 through 0.25.2 and hickory-resolver versions 0.26.0-alpha.1 before 0.26.2 are affected. The recursor follows every out-of-bailiwick name server target that lacks glue in a referral, without any per-query work limit (CWE-400). A remote attacker who serves such referrals can force A and AAAA lookups for each target, amplifying traffic against remote servers or exhausting recursor resources.

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

Description from the CNA

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.

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-dns0.26.0-alpha.1 to before 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 0.26.0-alpha.1 to before 0.26.2 Fixed in 0.26.2 Patch available CNA

Remediation

Upgrade hickory-resolver to version 0.26.2. The sources list no fixed version for hickory-recursor.

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-2026-86747 DNSSEC validation bypass in Hickory DNS via RRSIG signer namePriority MEDIUM 53
    • TI-2026-86746 Unbounded retry loop in Hickory DNS resolver enables resource exhaustionPriority MEDIUM 53
    Show all 36 records →

Timeline

  1. 2026-11-08 Threatist record created from CVE-2026-123606
  2. 2026-11-08 Alias added: GHSA-5p73-2jm7-2cmq

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-2026-86747 DNSSEC validation bypass in Hickory DNS via RRSIG signer name 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