{"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"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "packageURL": "pkg:cargo/hickory-recursor", "product": "hickory-dns", "vendor": "hickory-dns", "versions": [{"lessThanOrEqual": "0.26.0-alpha.1", "status": "affected", "version": "0.25.0-alpha.3", "versionType": "semver"}]}, {"defaultStatus": "unaffected", "packageURL": "pkg:cargo/hickory-resolver", "product": "hickory-dns", "vendor": "hickory-dns", "versions": [{"lessThan": "0.26.2", "status": "affected", "version": "0.26.0", "versionType": "semver"}, {"status": "unaffected", "version": "0.26.2", "versionType": "semver"}]}, {"defaultStatus": "unaffected", "packageURL": "pkg:cargo/hickory-proto", "product": "hickory-dns", "vendor": "hickory-dns", "versions": [{"lessThan": "0.26.2", "status": "affected", "version": "0.26.0", "versionType": "semver"}, {"status": "unaffected", "version": "0.26.2", "versionType": "semver"}]}, {"defaultStatus": "unaffected", "packageURL": "pkg:cargo/hickory-server", "product": "hickory-dns", "vendor": "hickory-dns", "versions": [{"lessThan": "0.26.2", "status": "affected", "version": "0.25.0-alpha.1", "versionType": "semver"}, {"status": "unaffected", "version": "0.26.2", "versionType": "semver"}]}], "source": "disclosure@vulncheck.com"}], "cveTags": [], "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."}], "id": "CVE-2026-123603", "lastModified": "2026-11-10T22:15:59.797", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 6.5, "baseSeverity": "MEDIUM", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 2.5, "source": "disclosure@vulncheck.com", "type": "Primary"}], "cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "NONE", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 6.9, "baseSeverity": "MEDIUM", "confidentialityRequirement": "NOT_DEFINED", "exploitMaturity": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "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/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", "version": "4.0", "vulnAvailabilityImpact": "NONE", "vulnConfidentialityImpact": "LOW", "vulnIntegrityImpact": "LOW", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "disclosure@vulncheck.com", "type": "Secondary"}]}, "published": "2026-11-08T02:16:55.117", "references": [{"source": "disclosure@vulncheck.com", "url": "https://github.com/hickory-dns/hickory-dns/security/advisories/GHSA-4jwp-xjwm-333g"}, {"source": "disclosure@vulncheck.com", "url": "https://www.vulncheck.com/advisories/hickory-dns-missing-ipv4-mapped-ipv6-canonicalization-access-control-bypass"}], "sourceIdentifier": "disclosure@vulncheck.com", "vulnStatus": "Deferred", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-284"}], "source": "disclosure@vulncheck.com", "type": "Primary"}]}

{}

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