CVE-2026-123585

Description

The hickory-resolver component of Hickory DNS 0.25.0 before 0.26.2 follows irrelevant CNAME records when resolving recursive queries, sending queries that are unnecessary to answer the original request. Attackers controlling DNS responses can include CNAME records in the authority or additional sections, or outside the original query name's CNAME chain, causing excess resolver queries and increased query amplification.

Overview

State: PUBLISHED
Assigner (CNA): VulnCheck
CVSS severity: MEDIUM
CVSS score: 6.9 / 10
CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
Effective score: 6.9 / 10 MEDIUM source: CNA overview
CWE(s): CWE-400
Reserved: 2026-11-06
Published: 2026-11-08 01:38 UTC
Last updated: 2026-11-08 01:38 UTC
Source: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/123xxx/CVE-2026-123585.json

European Union Vulnerability Database ENISA EUVD

ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.

EUVD ID: EUVD-2026-119344

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Affected products (1)

Vendor	Product	Versions	Platforms
hickory-dns	hickory-dns	`0.25.0` (affected), `0.26.2` (unaffected)	—

Vendor references (2)

References embedded in the original CVE record by the assigning CNA.

GitHub Security Advisory (GHSA-6f2x-v7q7-m7m5) vendor-advisory
VulnCheck Advisory: Hickory DNS 0.25.0 before 0.26.2 Query Amplification via Irrelevant CNAME Records third-party-advisory

Web references (0)

DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.

No web references attached yet.

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Raw JSON

The full cvelistV5 record. Download as CVE-2026-123585.json.

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "packageURL": "pkg:cargo/hickory-resolver",
          "product": "hickory-dns",
          "vendor": "hickory-dns",
          "versions": [
            {
              "lessThan": "0.26.2",
              "status": "affected",
              "version": "0.25.0",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "0.26.2",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "reporter",
          "value": "qifan-sailboat"
        }
      ],
      "datePublic": "2026-09-03T00:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "The hickory-resolver component of Hickory DNS 0.25.0 before 0.26.2 follows irrelevant CNAME records when resolving recursive queries, sending queries that are unnecessary to answer the original request. Attackers controlling DNS responses can include CNAME records in the authority or additional sections, or outside the original query name's CNAME chain, causing excess resolver queries and increased query amplification."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "Automatable": "NOT_DEFINED",
            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 6.9,
            "baseSeverity": "MEDIUM",
            "exploitMaturity": "NOT_DEFINED",
            "privilegesRequired": "NONE",
            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "LOW",
            "vulnConfidentialityImpact": "NONE",
            "vulnIntegrityImpact": "NONE",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
          },
          "format": "CVSS"
        },
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "LOW",
            "baseScore": 5.3,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
            "version": "3.1"
          },
          "format": "CVSS"
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-400",
              "description": "Uncontrolled Resource Consumption",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-11-08T01:38:18.261Z",
        "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
        "shortName": "VulnCheck"
      },
      "references": [
        {
          "name": "GitHub Security Advisory (GHSA-6f2x-v7q7-m7m5)",
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://github.com/hickory-dns/hickory-dns/security/advisories/GHSA-6f2x-v7q7-m7m5"
        },
        {
          "name": "VulnCheck Advisory: Hickory DNS 0.25.0 before 0.26.2 Query Amplification via Irrelevant CNAME Records",
          "tags": [
            "third-party-advisory"
          ],
          "url": "https://www.vulncheck.com/advisories/hickory-dns-0.25.0-before-0.26.2-query-amplification-via-irrelevant-cname-records"
        }
      ],
      "title": "Hickory DNS 0.25.0 before 0.26.2 Query Amplification via Irrelevant CNAME Records",
      "x_generator": {
        "engine": "vulncheck-endgame"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
    "assignerShortName": "VulnCheck",
    "cveId": "CVE-2026-123585",
    "datePublished": "2026-11-08T01:38:18.261Z",
    "dateReserved": "2026-11-06T00:57:31.044Z",
    "dateUpdated": "2026-11-08T01:38:18.261Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}