What is CVE-2026-123570?

CVE-2026-123570 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-2026-123570?

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

Resource exhaustion in Hickory-Dns

CVE-2026-123570

The DNS wire-format message parser in hickory-proto (Hickory DNS) 0.18 before 0.26.2 preallocates record vectors sized by the untrusted ANCOUNT, NSCOUNT, and ARCOUNT header fields before reading record data. Remote attackers can send a UDP datagram, or a spoofed response to a client/resolver, with these counts set to 65535, forcing about 18MB of allocation per message.

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-67wc-6jq8-ghrc) (vendor-advisory)
VulnCheck Advisory: Hickory DNS from 0.18 before 0.26.2 Memory Amplification DoS via RR Counts (third-party-advisory)

Frequently asked questions

What is CVE-2026-123570?: CVE-2026-123570 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-2026-123570?: High severity. CVSS v3 base score is 7.5 out of 10.