{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-66303", "assignerOrgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8", "state": "PUBLISHED", "assignerShortName": "microsoft", "dateReserved": "2026-07-24T18:06:51.294Z", "datePublished": "2026-09-08T18:39:43.900Z", "dateUpdated": "2026-09-08T18:39:43.900Z"}, "containers": {"cna": {"title": "Skype for Business and Lync Denial of Service Vulnerability", "datePublic": "2026-09-08T14:00:00.000Z", "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:microsoft:skype_for_business_server_2015:*:cu13:*:*:*:*:*:*", "versionStartIncluding": "9319.0", "versionEndExcluding": "6.0.9319.885"}, {"vulnerable": true, "criteria": "cpe:2.3:a:microsoft:skype_for_business_server_2019:*:cu8:*:*:*:*:*:*", "versionStartIncluding": "2046.0", "versionEndExcluding": "7.0.2046.569"}, {"vulnerable": true, "criteria": "cpe:2.3:a:microsoft:skype_for_business_server_subscription_edition:*:cu1:*:*:*:*:*:*", "versionStartIncluding": "2046.0", "versionEndExcluding": "7.0.2046.879"}]}]}], "affected": [{"vendor": "Microsoft", "product": "Skype for Business Server 2015 CU13", "platforms": ["x64-based Systems"], "versions": [{"version": "9319.0", "lessThan": "6.0.9319.885", "versionType": "custom", "status": "affected"}]}, {"vendor": "Microsoft", "product": "Skype for Business Server 2019 CU8", "platforms": ["x64-based Systems"], "versions": [{"version": "2046.0", "lessThan": "7.0.2046.569", "versionType": "custom", "status": "affected"}]}, {"vendor": "Microsoft", "product": "Skype for Business Server Subscription Edition CU1", "platforms": ["x64-based Systems"], "versions": [{"version": "2046.0", "lessThan": "7.0.2046.879", "versionType": "custom", "status": "affected"}]}], "descriptions": [{"value": "Null pointer dereference in Skype for Business allows an authorized attacker to deny service over a network.", "lang": "en-US"}], "problemTypes": [{"descriptions": [{"description": "CWE-476: NULL Pointer Dereference", "lang": "en-US", "type": "CWE", "cweId": "CWE-476"}]}], "providerMetadata": {"orgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8", "shortName": "microsoft", "dateUpdated": "2026-09-08T18:39:43.900Z"}, "references": [{"name": "Skype for Business and Lync Denial of Service Vulnerability", "tags": ["vendor-advisory", "patch"], "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-66303"}], "metrics": [{"format": "CVSS", "scenarios": [{"lang": "en-US", "value": "GENERAL"}], "cvssV3_1": {"version": "3.1", "baseSeverity": "MEDIUM", "baseScore": 6.5, "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C"}}]}}}

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{"affected": [{"affectedData": [{"platforms": ["x64-based Systems"], "product": "Skype for Business Server 2015 CU13", "vendor": "Microsoft", "versions": [{"lessThan": "6.0.9319.885", "status": "affected", "version": "9319.0", "versionType": "custom"}]}, {"platforms": ["x64-based Systems"], "product": "Skype for Business Server 2019 CU8", "vendor": "Microsoft", "versions": [{"lessThan": "7.0.2046.569", "status": "affected", "version": "2046.0", "versionType": "custom"}]}, {"platforms": ["x64-based Systems"], "product": "Skype for Business Server Subscription Edition CU1", "vendor": "Microsoft", "versions": [{"lessThan": "7.0.2046.879", "status": "affected", "version": "2046.0", "versionType": "custom"}]}], "source": "secure@microsoft.com"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Null pointer dereference in Skype for Business allows an authorized attacker to deny service over a network."}], "id": "CVE-2026-66303", "lastModified": "2026-09-08T19:22:18.470", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 6.5, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 2.8, "impactScore": 3.6, "source": "secure@microsoft.com", "type": "Primary"}]}, "published": "2026-09-08T19:18:07.820", "references": [{"source": "secure@microsoft.com", "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-66303"}], "sourceIdentifier": "secure@microsoft.com", "vulnStatus": "Awaiting Analysis", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-476"}], "source": "secure@microsoft.com", "type": "Primary"}]}

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