What is CVE-2026-123573?

CVE-2026-123573 is a high-severity vulnerability in Hickory-Dns, classified under Improper Input Validation. CVSS score: 7.5/10. Published 2026-11-08.

How severe is CVE-2026-123573?

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

Improper input validation in Hickory-Dns

CVE-2026-123573

hickory-dns from 0.20.1 before 0.26.2 contains a denial of service vulnerability in the hickory-proto SVCB and HTTPS record presentation format parser. Attackers can supply untrusted zone files where only a single or double quote replaces a service parameter value, triggering a panic that crashes the parsing process.

Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)

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

EPSS: 0.003 (28.1th percentile), scored 2026-11-09.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 28th percentile — 28.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

The 30-day trend appears once there are two daily scores.

Affected products

Hickory-Dns

Weakness classification (CWE)

CWE-20 — Improper Input Validation

References

github.com/hickory-dns/hickory-dns/security/advisories/GHSA-wgfr-mphw-j5g4 (vendor-advisory)
www.vulncheck.com/advisories/hickory-dns-from-0.20.1-before-0.26.2-panic-in-svc… (third-party-advisory)

Frequently asked questions

What is CVE-2026-123573?: CVE-2026-123573 is a high-severity vulnerability in Hickory-Dns, classified under Improper Input Validation. CVSS score: 7.5/10. Published 2026-11-08.
How severe is CVE-2026-123573?: High severity. CVSS v3 base score is 7.5 out of 10.