What is CVE-2026-123586?

CVE-2026-123586 is a high-severity vulnerability in Hickory-Dns, classified under Uncontrolled Resource Consumption. CVSS score: 7.5/10. Published 2026-11-08.

How severe is CVE-2026-123586?

High severity. CVSS v3 base score is 7.5 out of 10.

Resource exhaustion in Hickory-Dns

CVE-2026-123586

Hickory DNS 0.25.0-alpha.3 through 0.25.2 contains a query amplification vulnerability in its recursive resolver, which mishandles cyclic sibling name server referrals that lack glue records. Attackers controlling two zones whose name servers reference each other without glue records can make the recursor loop, sending many upstream queries, amplified further by zero-TTL NS records.

Vulnerability class: DoS (Denial of Service)

Published 2026-11-08.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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-400 — Uncontrolled Resource Consumption

References

GitHub Security Advisory (GHSA-cx5j-p54p-q756) (vendor-advisory)
VulnCheck Advisory: Hickory DNS 0.25.0-alpha.3 through 0.25.2 Query Amplification via Cyclic Referrals (third-party-advisory)

Frequently asked questions

What is CVE-2026-123586?: CVE-2026-123586 is a high-severity vulnerability in Hickory-Dns, classified under Uncontrolled Resource Consumption. CVSS score: 7.5/10. Published 2026-11-08.
How severe is CVE-2026-123586?: High severity. CVSS v3 base score is 7.5 out of 10.