Vulnerability Description
Hickory DNS hickory-proto through 0.26.0-alpha.1 and hickory-net 0.26.0-beta.1 before 0.26.2 contain a DNSSEC validation flaw in the validating recursor's NSEC handler that accepts parent-side ancestor-delegation NSEC records as proof of nonexistence for names below the zone cut. An on-path attacker, rogue parent nameserver, or attacker winning a port and TXID race can deliver one forged NXDOMAIN response built from genuinely signed parent NSEC records, causing authenticated denial of existing child-zone names cached for the negative TTL.
CVSS Score
HIGH
Related Weaknesses (CWE)
References
- https://github.com/hickory-dns/hickory-dns/security/advisories/GHSA-3r6v-f3jh-vv
- https://www.vulncheck.com/advisories/hickory-dns-through-0.26.0-alpha.1-dnssec-v
FAQ
What is CVE-2026-123596?
CVE-2026-123596 is a vulnerability with a CVSS score of 8.8 (HIGH). Hickory DNS hickory-proto through 0.26.0-alpha.1 and hickory-net 0.26.0-beta.1 before 0.26.2 contain a DNSSEC validation flaw in the validating recursor's NSEC handler that accepts parent-side ancesto...
How severe is CVE-2026-123596?
CVE-2026-123596 has been rated HIGH with a CVSS base score of 8.8/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-123596?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.