What is CVE-2026-123594?

CVE-2026-123594 is a medium-severity vulnerability in Hickory-Dns, classified under Insufficient Verification of Data Authenticity. CVSS score: 4.8/10. Published 2026-11-08.

How severe is CVE-2026-123594?

Medium severity. CVSS v3 base score is 4.8 out of 10.

Vulnerability in Hickory-Dns

CVE-2026-123594

Hickory DNS hickory-proto through 0.26.0-alpha.1 and hickory-net 0.26.0-beta.1 before 0.26.2 contain an NSEC validation flaw that returns a secure proof for NXDOMAIN responses when the covering NSEC's Next Domain Name is a strict descendant of the query name, which actually proves the name exists as an empty non-terminal. On-path attackers can flip the unsigned rcode of a genuine signed NODATA response from NOERROR to NXDOMAIN, causing validators to accept forged nonexistence of the name.

Published 2026-11-08.

CVSS v3 metric

CVSS v3 base score 4.8 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Hickory-Dns

Weakness classification (CWE)

CWE-345 — Insufficient Verification of Data Authenticity

References

GitHub Security Advisory (GHSA-86vr-jm6c-7cpg) (vendor-advisory)
VulnCheck Advisory: Hickory DNS through 0.26.0-alpha.1 DNSSEC NSEC Validation Bypass for Empty Non-Terminals (third-party-advisory)

Frequently asked questions

What is CVE-2026-123594?: CVE-2026-123594 is a medium-severity vulnerability in Hickory-Dns, classified under Insufficient Verification of Data Authenticity. CVSS score: 4.8/10. Published 2026-11-08.
How severe is CVE-2026-123594?: Medium severity. CVSS v3 base score is 4.8 out of 10.