CVE-2026-6736

{"id": "CVE-2026-6736", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-6736", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-05-08T13:57:09.447908Z"}}], "cvssMetricV31": [{"type": "Primary", "source": "nvd@nist.gov", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 6.5, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N", "integrityImpact": "LOW", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "NONE", "confidentialityImpact": "LOW"}, "impactScore": 2.5, "exploitabilityScore": 3.9}], "cvssMetricV40": [{"type": "Secondary", "source": "product-cna@github.com", "cvssData": {"Safety": "NOT_DEFINED", "version": "4.0", "Recovery": "NOT_DEFINED", "baseScore": 6.3, "Automatable": "NOT_DEFINED", "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/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", "exploitMaturity": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "userInteraction": "NONE", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "privilegesRequired": "NONE", "subIntegrityImpact": "NONE", "vulnIntegrityImpact": "NONE", "integrityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "vulnAvailabilityImpact": "NONE", "availabilityRequirement": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "subConfidentialityImpact": "NONE", "vulnConfidentialityImpact": "LOW", "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": "product-cna@github.com", "affectedData": [{"vendor": "GitHub", "product": "Enterprise Server", "versions": [{"status": "affected", "changes": [{"at": "3.16.18", "status": "unaffected"}], "version": "3.16.0", "versionType": "semver", "lessThanOrEqual": "3.16.17"}, {"status": "affected", "changes": [{"at": "3.17.15", "status": "unaffected"}], "version": "3.17.0", "versionType": "semver", "lessThanOrEqual": "3.17.14"}, {"status": "affected", "changes": [{"at": "3.18.9", "status": "unaffected"}], "version": "3.18.0", "versionType": "semver", "lessThanOrEqual": "3.18.8"}, {"status": "affected", "changes": [{"at": "3.19.6", "status": "unaffected"}], "version": "3.19.0", "versionType": "semver", "lessThanOrEqual": "3.19.5"}, {"status": "affected", "changes": [{"at": "3.20.2", "status": "unaffected"}], "version": "3.20.0", "versionType": "semver", "lessThanOrEqual": "3.20.1"}], "defaultStatus": "affected"}]}], "published": "2026-05-07T22:16:36.753", "references": [{"url": "https://docs.github.com/en/enterprise-server@3.16/admin/release-notes#3.16.18", "tags": ["Release Notes", "Vendor Advisory"], "source": "product-cna@github.com"}, {"url": "https://docs.github.com/en/enterprise-server@3.17/admin/release-notes#3.17.15", "tags": ["Release Notes", "Vendor Advisory"], "source": "product-cna@github.com"}, {"url": "https://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.9", "tags": ["Release Notes", "Vendor Advisory"], "source": "product-cna@github.com"}, {"url": "https://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.6", "tags": ["Release Notes", "Vendor Advisory"], "source": "product-cna@github.com"}, {"url": "https://docs.github.com/en/enterprise-server@3.20/admin/release-notes#3.20.2", "tags": ["Release Notes", "Vendor Advisory"], "source": "product-cna@github.com"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Secondary", "source": "product-cna@github.com", "description": [{"lang": "en", "value": "CWE-306"}]}], "descriptions": [{"lang": "en", "value": "An authentication bypass vulnerability was identified in GitHub Enterprise Server that allowed an unauthenticated attacker to create a local user account, bypassing the configured external identity provider. When external authentication was enabled, the signup endpoint did not properly enforce the authentication restriction, allowing account creation and session establishment without identity provider validation. The created account was limited to the default base permissions configured on the instance. Exploitation required network access to a GHES instance configured with an external authentication provider. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.21 and was fixed in versions 3.20.2, 3.19.6, 3.18.9, 3.17.15, and 3.16.18."}, {"lang": "es", "value": "Una vulnerabilidad de omisi\u00f3n de autenticaci\u00f3n fue identificada en GitHub Enterprise Server que permit\u00eda a un atacante no autenticado crear una cuenta de usuario local, omitiendo el proveedor de identidad externo configurado. Cuando la autenticaci\u00f3n externa estaba habilitada, el endpoint de registro no aplicaba correctamente la restricci\u00f3n de autenticaci\u00f3n, permitiendo la creaci\u00f3n de cuentas y el establecimiento de sesiones sin validaci\u00f3n del proveedor de identidad. La cuenta creada estaba limitada a los permisos base predeterminados configurados en la instancia. La explotaci\u00f3n requer\u00eda acceso de red a una instancia de GHES configurada con un proveedor de autenticaci\u00f3n externo. Esta vulnerabilidad afect\u00f3 a todas las versiones de GitHub Enterprise Server anteriores a la 3.21 y fue corregida en las versiones 3.20.2, 3.19.6, 3.18.9, 3.17.15 y 3.16.18."}], "lastModified": "2026-10-26T20:10:00.160", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "30904527-43B5-453A-A669-7845C2643965", "versionEndExcluding": "3.16.18"}, {"criteria": "cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "D594E173-80DE-4EC9-9E6C-8C78A80D1402", "versionEndExcluding": "3.17.15", "versionStartIncluding": "3.17.0"}, {"criteria": "cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "2501EC91-4CD0-49F5-B76A-558EB5A5946C", "versionEndExcluding": "3.18.9", "versionStartIncluding": "3.18.0"}, {"criteria": "cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "F2D6ABE3-EF68-4DDC-9846-9A891C859477", "versionEndExcluding": "3.19.6", "versionStartIncluding": "3.19.0"}, {"criteria": "cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "FC8A09E8-5FFE-43F1-BC1A-14A298264D80", "versionEndExcluding": "3.20.2", "versionStartIncluding": "3.20.0"}], "operator": "OR"}]}], "sourceIdentifier": "product-cna@github.com"}