CVE-2026-33278

{"id": "CVE-2026-33278", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-33278", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "total"}], "version": "2.0.3", "timestamp": "2026-05-20T12:13:01.681597Z"}}], "cvssMetricV31": [{"type": "Primary", "source": "nvd@nist.gov", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 9.8, "attackVector": "NETWORK", "baseSeverity": "CRITICAL", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "HIGH"}, "impactScore": 5.9, "exploitabilityScore": 3.9}, {"type": "Secondary", "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 8.1, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "HIGH", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "HIGH"}, "impactScore": 5.9, "exploitabilityScore": 2.2}], "cvssMetricV40": [{"type": "Secondary", "source": "sep@nlnetlabs.nl", "cvssData": {"Safety": "NOT_DEFINED", "version": "4.0", "Recovery": "NOT_DEFINED", "baseScore": 9.1, "Automatable": "NOT_DEFINED", "attackVector": "NETWORK", "baseSeverity": "CRITICAL", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:U/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:Red", "exploitMaturity": "UNREPORTED", "providerUrgency": "RED", "userInteraction": "NONE", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "subIntegrityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "integrityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "subAvailabilityImpact": "HIGH", "vulnAvailabilityImpact": "HIGH", "availabilityRequirement": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "subConfidentialityImpact": "HIGH", "vulnConfidentialityImpact": "HIGH", "confidentialityRequirement": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED"}}]}, "affected": [{"source": "sep@nlnetlabs.nl", "affectedData": [{"vendor": "NLnet Labs", "product": "Unbound", "versions": [{"status": "affected", "version": "1.19.1", "lessThan": "1.25.1", "versionType": "semver"}], "defaultStatus": "unaffected"}]}, {"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c", "affectedData": [{"cpes": ["cpe:/o:redhat:enterprise_linux:10.2"], "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 10", "versions": [{"status": "unaffected", "version": "0:1.24.2-7.el10_2.1", "lessThan": "*", "versionType": "rpm"}], "packageName": "unbound", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "affected"}, {"cpes": ["cpe:/a:redhat:enterprise_linux:9"], "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 9", "versions": [{"status": "unaffected", "version": "0:1.24.2-3.el9_8.1", "lessThan": "*", "versionType": "rpm"}], "packageName": "unbound", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "affected"}, {"cpes": ["cpe:/a:redhat:hummingbird:1"], "vendor": "Red Hat", "product": "Red Hat Hardened Images", "versions": [{"status": "unaffected", "version": "1.25.1-0.1.hum1", "lessThan": "*", "versionType": "rpm"}], "packageName": "unbound-main", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "affected"}, {"cpes": ["cpe:/o:redhat:enterprise_linux:6"], "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 6", "packageName": "unbound", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "unknown"}, {"cpes": ["cpe:/o:redhat:enterprise_linux:7"], "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 7", "packageName": "unbound", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "unaffected"}, {"cpes": ["cpe:/o:redhat:enterprise_linux:8"], "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 8", "packageName": "unbound", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "unaffected"}, {"cpes": ["cpe:/a:redhat:openshift:4"], "vendor": "Red Hat", "product": "Red Hat OpenShift Container Platform 4", "packageName": "rhcos", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "affected"}]}], "published": "2026-05-20T10:16:26.530", "references": [{"url": "https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-33278.txt", "tags": ["Mitigation", "Vendor Advisory"], "source": "sep@nlnetlabs.nl"}, {"url": "https://access.redhat.com/errata/RHSA-2026:19752", "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"}, {"url": "https://access.redhat.com/errata/RHSA-2026:23231", "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"}, {"url": "https://access.redhat.com/errata/RHSA-2026:24369", "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"}, {"url": "https://access.redhat.com/security/cve/CVE-2026-33278", "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"}, {"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2479808", "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"}, {"url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33278.json", "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"}], "vulnStatus": "Modified", "weaknesses": [{"type": "Secondary", "source": "sep@nlnetlabs.nl", "description": [{"lang": "en", "value": "CWE-416"}, {"lang": "en", "value": "CWE-672"}]}, {"type": "Secondary", "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c", "description": [{"lang": "en", "value": "CWE-416"}]}], "descriptions": [{"lang": "en", "value": "NLnet Labs Unbound 1.19.1 up to and including version 1.25.0 has a vulnerability in the DNSSEC validator that enables denial of service and possible remote code execution as a result of deep copying a data structure and erroneously overwriting a destination pointer. An adversary can exploit the vulnerability by controlling a malicious signed zone and querying a vulnerable Unbound. When DS sub-queries need to suspend validation due to NSEC3 computational budget exhaustion (introduced in Unbound 1.19.1), Unbound deep-copies response messages to preserve them across memory region teardown. A struct-assignment bug overwrites the destination's pointer with the source's pointer. After the sub-query region is freed, the resumed validator dereferences this dangling pointer, triggering a crash or potentially enabling arbitrary code execution. Unbound 1.25.1 contains a patch with a fix to preserve the correct pointer when deep copying the data structure."}, {"lang": "es", "value": "NLnet Labs Unbound 1.19.1 hasta la versi\u00f3n 1.25.0 inclusive tiene una vulnerabilidad en el validador DNSSEC que permite la denegaci\u00f3n de servicio y posible ejecuci\u00f3n remota de c\u00f3digo como resultado de la copia profunda de una estructura de datos y la sobrescritura err\u00f3nea de un puntero de destino. Un adversario puede explotar la vulnerabilidad controlando una zona firmada maliciosa y consultando un Unbound vulnerable. Cuando las subconsultas DS necesitan suspender la validaci\u00f3n debido al agotamiento del presupuesto computacional de NSEC3 (introducido en Unbound 1.19.1), Unbound realiza copias profundas de los mensajes de respuesta para preservarlos durante la desasignaci\u00f3n de la regi\u00f3n de memoria. Un error de asignaci\u00f3n de estructura sobrescribe el puntero del destino con el puntero del origen. Despu\u00e9s de que se libera la regi\u00f3n de la subconsulta, el validador reanudado desreferencia este puntero colgante, lo que provoca un fallo o potencialmente permite la ejecuci\u00f3n de c\u00f3digo arbitrario. Unbound 1.25.1 contiene un parche con una correcci\u00f3n para preservar el puntero correcto al realizar la copia profunda de la estructura de datos."}], "lastModified": "2026-07-24T10:10:00.197", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:nlnetlabs:unbound:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "5C330C7D-8CBA-407E-9C85-8BB7D5A97797", "versionEndExcluding": "1.25.1", "versionStartIncluding": "1.19.1"}], "operator": "OR"}]}], "sourceIdentifier": "sep@nlnetlabs.nl"}