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TI-2026-86739 Aliases CVE-2026-123597GHSA-2v9q-m22g-rqg6

Hickory DNS DNSSEC Validation Cache Poisoning via Transient DS-Fetch Errors

Priority LOW 27CWE-613Published · Updated

Key facts

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

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-613.

Summary

hickory-proto 0.25.0-alpha.1 through 0.26.0-alpha.1 and hickory-net before 0.26.2 are affected. A logic bug in the DS-fetch path of DnssecDnsHandle caches transient DS lookup errors as Bogus DNSSEC validation verdicts. An unauthenticated remote attacker who induces a SERVFAIL, REFUSED, or timeout response to a child-zone DS sub-query makes the validator return SERVFAIL for all names under that zone until the cache entry's TTL expires.

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

Description from the CNA

Hickory DNS hickory-proto 0.25.0-alpha.1 through 0.26.0-alpha.1 and hickory-net before 0.26.2 contain a logic bug in DnssecDnsHandle's DS-fetch path that caches transient DS lookup errors as Bogus DNSSEC validation verdicts. An attacker who induces a SERVFAIL, REFUSED, or timeout response to a child-zone DS sub-query causes the validator to return SERVFAIL for all names under that zone until the cache entry's TTL expires.

Why it matters now

EPSS 0.00218 12th 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-alpha.1 – 0.26.0-alpha.1—No fix listedCNA
hickory-dnshickory-dns0.26.0-beta.1 to before 0.26.20.26.2Patch availableCNA
  • hickory-dns Vendorhickory-dns Affected 0.25.0-alpha.1 – 0.26.0-alpha.1 Fixed in — No fix listed CNA
  • hickory-dns Vendorhickory-dns Affected 0.26.0-beta.1 to before 0.26.2 Fixed in 0.26.2 Patch available CNA

Remediation

Hickory DNS 0.26.2 fixes the flaw for versions from 0.26.0-beta.1 before 0.26.2, so upgrade to 0.26.2. The sources list no fixed version for hickory-dns.

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-2026-123597
  2. 2026-11-08 Alias added: GHSA-2v9q-m22g-rqg6
  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