# CVE-2026-123573: hickory-dns from 0.20.1 before 0.26.2 Panic in SVCB/HTTPS Zone File Parser

Status: published. Published: 2026-11-08. Updated: 2026-11-10.

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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- hickory-dns / hickory-dns (hickory-proto): ≥ 0.20.1; < 0.26.2 (affected, semver); 0.26.2 (unaffected, semver). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 8.7 (high); CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 7.5 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H; source: CNA: VulnCheck

- CVSS 4.0: 8.7 (high); CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X; source: NVD: disclosure@vulncheck.com

- CVSS 3.1: 7.5 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H; source: NVD: disclosure@vulncheck.com

- CISA KEV: No listing in collected sources

- EPSS: 0.34% as of 2026-11-10; percentile 28.14%

- SSVC: exploitation none; automatable yes; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-20

## 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-wgfr-mphw-j5g4 (CNA: VulnCheck; vendor-advisory)

- https://www.vulncheck.com/advisories/hickory-dns-from-0.20.1-before-0.26.2-panic-in-svcb-https-zone-file-parser (CNA: VulnCheck; third-party-advisory)

- https://github.com/hickory-dns/hickory-dns/security/advisories/GHSA-wgfr-mphw-j5g4 (disclosure@vulncheck.com)

- https://www.vulncheck.com/advisories/hickory-dns-from-0.20.1-before-0.26.2-panic-in-svcb-https-zone-file-parser (disclosure@vulncheck.com)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-123573; retrieved 2026-11-10; source updated 2026-11-10

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-123573; retrieved 2026-11-08; source updated 2026-11-08

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-123573; retrieved 2026-11-10; source updated Not reported

Revision: eabea73566ec9afcd4004f61f42138c569c6b170c3ee901815d848f1d5a40079

Canonical: https://y2.dev/cve/CVE-2026-123573

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