{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-20856", "assignerOrgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8", "state": "PUBLISHED", "assignerShortName": "microsoft", "dateReserved": "2025-12-03T05:54:20.380Z", "datePublished": "2026-01-13T17:56:30.668Z", "dateUpdated": "2026-01-13T18:04:16.712Z"}, "containers": {"cna": {"title": "Windows Server Update Service (WSUS) Remote Code Execution Vulnerability", "datePublic": "2026-01-13T08:00:00.000Z", "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x86:*", "versionStartIncluding": "10.0.17763.0", "versionEndExcluding": "10.0.17763.8276"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:*", "versionStartIncluding": "10.0.17763.0", "versionEndExcluding": "10.0.17763.8276"}, {"vulnerable": true, "criteria": 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{}

{"cveTags": [], "descriptions": [{"lang": "en", "value": "Improper input validation in Windows Server Update Service allows an unauthorized attacker to execute code over a network."}], "id": "CVE-2026-20856", "lastModified": "2026-01-13T18:16:14.313", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 8.1, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 2.2, "impactScore": 5.9, "source": "secure@microsoft.com", "type": "Primary"}]}, "published": "2026-01-13T18:16:14.313", "references": [{"source": "secure@microsoft.com", "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20856"}], "sourceIdentifier": "secure@microsoft.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-20"}], "source": "secure@microsoft.com", "type": "Primary"}]}

{}

{}