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TI-2026-86743 Aliases CVE-2026-123601GHSA-hj9x-wc4q-vmw3

Inverted NSEC3 operators in Hickory DNS let forged negative responses

Priority MEDIUM 51CWE-480Published · Updated

Key facts

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

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

Summary

The hickory-proto crate from 0.25.0 through 0.26.0-alpha.1 and the hickory-net crate from 0.26.0-beta.1 before 0.26.2 are affected. Their NSEC3 covering-record lookup inverts a comparison in the wrap-around branch, so the last NSEC3 record in a zone covers every hash except its owner (CWE-480). An attacker who can inject DNS responses can replay that record and its RRSIG to forge DNSSEC-validated negative responses denying legitimate names.

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

Description from the CNA

Hickory DNS hickory-proto 0.25.0 through 0.26.0-alpha.1 and hickory-net 0.26.0-beta.1 before 0.26.2 invert the relational operators in the wrap-around branch of find_covering_record() in nsec3.rs, so the last NSEC3 record in a zone's hash ring covers every hash except its owner. Attackers able to inject DNS responses can replay that NSEC3 record and its RRSIG to forge DNSSEC-validated negative responses denying legitimate names.

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-dns0.26.0-beta.1 to before 0.26.20.26.2Patch availableCNA
hickory-dnshickory-dns0.25.0 – 0.26.0-alpha.1—No fix listedCNA
  • hickory-dns Vendorhickory-dns Affected 0.26.0-beta.1 to before 0.26.2 Fixed in 0.26.2 Patch available CNA
  • hickory-dns Vendorhickory-dns Affected 0.25.0 – 0.26.0-alpha.1 Fixed in — No fix listed CNA

Remediation

Update hickory-net to 0.26.2, which fixes this issue. The sources list no fixed version for hickory-proto.

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-2026-123601
  2. 2026-11-08 Alias added: GHSA-hj9x-wc4q-vmw3

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