{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-123603",
        "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
        "state": "PUBLISHED",
        "assignerShortName": "VulnCheck",
        "dateReserved": "2026-11-06T01:00:16.506Z",
        "datePublished": "2026-11-08T01:38:30.679Z",
        "dateUpdated": "2026-11-08T01:38:30.679Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
                "shortName": "VulnCheck",
                "dateUpdated": "2026-11-08T01:38:30.679Z"
            },
            "datePublic": "2026-09-03T00:00:00.000Z",
            "title": "Hickory DNS Missing IPv4-Mapped IPv6 Canonicalization Access Control Bypass",
            "descriptions": [
                {
                    "lang": "en",
                    "value": "hickory-proto and hickory-resolver 0.26.0 before 0.26.2, hickory-server 0.25.0-alpha.1 before 0.26.2, and hickory-recursor 0.25.0-alpha.3 through 0.26.0-alpha.1 fail to canonicalize IPv4-mapped IPv6 addresses when checking deny_answers, deny_server, or AccessControlSet rules. Attackers can use IPv4-mapped addresses to evade answer filtering, trigger queries to denied nameservers, or reach hickory-server library deployments on dual-stack IPv6 sockets from denied clients."
                }
            ],
            "problemTypes": [
                {
                    "descriptions": [
                        {
                            "lang": "en",
                            "description": "Improper Access Control",
                            "cweId": "CWE-284",
                            "type": "CWE"
                        }
                    ]
                }
            ],
            "affected": [
                {
                    "vendor": "hickory-dns",
                    "product": "hickory-dns",
                    "defaultStatus": "unaffected",
                    "packageURL": "pkg:cargo/hickory-recursor",
                    "versions": [
                        {
                            "version": "0.25.0-alpha.3",
                            "status": "affected",
                            "versionType": "semver",
                            "lessThanOrEqual": "0.26.0-alpha.1"
                        }
                    ]
                },
                {
                    "vendor": "hickory-dns",
                    "product": "hickory-dns",
                    "defaultStatus": "unaffected",
                    "packageURL": "pkg:cargo/hickory-resolver",
                    "versions": [
                        {
                            "version": "0.26.0",
                            "status": "affected",
                            "versionType": "semver",
                            "lessThan": "0.26.2"
                        },
                        {
                            "version": "0.26.2",
                            "status": "unaffected",
                            "versionType": "semver"
                        }
                    ]
                },
                {
                    "vendor": "hickory-dns",
                    "product": "hickory-dns",
                    "defaultStatus": "unaffected",
                    "packageURL": "pkg:cargo/hickory-proto",
                    "versions": [
                        {
                            "version": "0.26.0",
                            "status": "affected",
                            "versionType": "semver",
                            "lessThan": "0.26.2"
                        },
                        {
                            "version": "0.26.2",
                            "status": "unaffected",
                            "versionType": "semver"
                        }
                    ]
                },
                {
                    "vendor": "hickory-dns",
                    "product": "hickory-dns",
                    "defaultStatus": "unaffected",
                    "packageURL": "pkg:cargo/hickory-server",
                    "versions": [
                        {
                            "version": "0.25.0-alpha.1",
                            "status": "affected",
                            "versionType": "semver",
                            "lessThan": "0.26.2"
                        },
                        {
                            "version": "0.26.2",
                            "status": "unaffected",
                            "versionType": "semver"
                        }
                    ]
                }
            ],
            "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:L/VI:L/VA:N/SC:N/SI:N/SA:N",
                        "version": "4.0",
                        "vulnAvailabilityImpact": "NONE",
                        "vulnConfidentialityImpact": "LOW",
                        "vulnIntegrityImpact": "LOW",
                        "vulnerabilityResponseEffort": "NOT_DEFINED"
                    },
                    "format": "CVSS"
                },
                {
                    "cvssV3_1": {
                        "version": "3.1",
                        "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N",
                        "attackVector": "NETWORK",
                        "attackComplexity": "LOW",
                        "privilegesRequired": "NONE",
                        "userInteraction": "NONE",
                        "scope": "UNCHANGED",
                        "confidentialityImpact": "LOW",
                        "integrityImpact": "LOW",
                        "availabilityImpact": "NONE",
                        "baseScore": 6.5,
                        "baseSeverity": "MEDIUM"
                    },
                    "format": "CVSS"
                }
            ],
            "references": [
                {
                    "url": "https://github.com/hickory-dns/hickory-dns/security/advisories/GHSA-4jwp-xjwm-333g",
                    "tags": [
                        "vendor-advisory"
                    ],
                    "name": "GitHub Security Advisory (GHSA-4jwp-xjwm-333g)"
                },
                {
                    "name": "VulnCheck Advisory: Hickory DNS Missing IPv4-Mapped IPv6 Canonicalization Access Control Bypass",
                    "tags": [
                        "third-party-advisory"
                    ],
                    "url": "https://www.vulncheck.com/advisories/hickory-dns-missing-ipv4-mapped-ipv6-canonicalization-access-control-bypass"
                }
            ],
            "credits": [
                {
                    "lang": "en",
                    "value": "qifan-sailboat",
                    "type": "reporter"
                }
            ],
            "x_generator": {
                "engine": "vulncheck-endgame"
            }
        }
    }
}