# CVE-2026-123601: Hickory DNS 0.26.0-beta.1 before 0.26.2 NSEC3 Proof of Nonexistence Forgery

Status: published. Published: 2026-11-08. Updated: 2026-11-08.

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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- hickory-dns / hickory-dns (hickory-net): ≥ 0.26.0-beta.1; < 0.26.2 (affected, semver); 0.26.2 (unaffected, semver). Source: CNA: VulnCheck
- hickory-dns / hickory-dns (hickory-proto): ≥ 0.25.0; ≤ 0.26.0-alpha.1 (affected, semver). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 8.3 (high); CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 6.5 (medium); CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H; source: CNA: VulnCheck

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-480

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/hickory-dns/hickory-dns/security/advisories/GHSA-588m-chg6-8jqj (CNA: VulnCheck; vendor-advisory)

- https://www.vulncheck.com/advisories/hickory-dns-0.26.0-beta.1-before-0.26.2-nsec3-proof-of-nonexistence-forgery (CNA: VulnCheck; third-party-advisory)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-123601; retrieved 2026-11-08; source updated 2026-11-08

Revision: 50e02a9a0e94982252f5aa835158ce4b0e4d94368813c750dc05da594a5608a9

Canonical: https://y2.dev/cve/CVE-2026-123601

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