{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-40366", "assignerOrgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8", "state": "PUBLISHED", "assignerShortName": "microsoft", "dateReserved": "2026-04-11T23:06:15.614Z", "datePublished": "2026-05-12T16:58:38.928Z", "dateUpdated": "2026-05-12T17:53:38.292Z"}, "containers": {"cna": {"title": "Microsoft Word Remote Code Execution Vulnerability", "datePublic": "2026-05-12T14:00:00.000Z", "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:microsoft:office_2019:*:*:*:*:*:*:*:*", "versionStartIncluding": "19.0.0", "versionEndExcluding": "https://aka.ms/OfficeSecurityReleases"}, {"vulnerable": true, "criteria": "cpe:2.3:a:microsoft:365_apps:*:*:*:*:enterprise:*:*:*", "versionStartIncluding": "16.0.1", "versionEndExcluding": "https://aka.ms/OfficeSecurityReleases"}, {"vulnerable": true, "criteria": "cpe:2.3:a:microsoft:office_macos_2021:*:*:*:*:*:long_term_servicing_channel:*:*", "versionStartIncluding": "16.0.1", "versionEndExcluding": "16.109.26051019"}, {"vulnerable": true, "criteria": "cpe:2.3:a:microsoft:office_2021:*:*:*:*:long_term_servicing_channel:*:*:*", "versionStartIncluding": "16.0.1", "versionEndExcluding": "https://aka.ms/OfficeSecurityReleases"}, {"vulnerable": true, "criteria": "cpe:2.3:a:microsoft:office_2024:*:*:*:*:long_term_servicing_channel:*:*:*", "versionStartIncluding": "16.0.0", "versionEndExcluding": "https://aka.ms/OfficeSecurityReleases"}, {"vulnerable": true, "criteria": "cpe:2.3:a:microsoft:office_macos_2024:*:*:*:*:*:long_term_servicing_channel:*:*", "versionStartIncluding": "16.0.0", "versionEndExcluding": "16.109.26051019"}, {"vulnerable": true, "criteria": "cpe:2.3:a:microsoft:word_2016:*:*:*:*:*:*:*:*", "versionStartIncluding": "16.0.1", "versionEndExcluding": "16.0.5552.1000"}]}]}], "affected": [{"vendor": "Microsoft", "product": "Microsoft 365 Apps for Enterprise", "platforms": ["32-bit Systems", "x64-based Systems"], "versions": [{"version": "16.0.1", "lessThan": "https://aka.ms/OfficeSecurityReleases", "versionType": "custom", "status": "affected"}]}, {"vendor": "Microsoft", "product": "Microsoft Office 2019", "platforms": ["32-bit Systems", "x64-based Systems"], "versions": [{"version": "19.0.0", "lessThan": "https://aka.ms/OfficeSecurityReleases", "versionType": "custom", "status": "affected"}]}, {"vendor": "Microsoft", "product": "Microsoft Office LTSC 2021", "platforms": ["32-bit Systems", "x64-based Systems"], "versions": [{"version": "16.0.1", "lessThan": "https://aka.ms/OfficeSecurityReleases", "versionType": "custom", "status": "affected"}]}, {"vendor": "Microsoft", "product": "Microsoft Office LTSC 2024", "platforms": ["32-bit Systems", "x64-based Systems"], "versions": [{"version": "16.0.0", "lessThan": "https://aka.ms/OfficeSecurityReleases", "versionType": "custom", "status": "affected"}]}, {"vendor": "Microsoft", "product": "Microsoft Office LTSC for Mac 2021", "versions": [{"version": "16.0.1", "lessThan": "16.109.26051019", "versionType": "custom", "status": "affected"}]}, {"vendor": "Microsoft", "product": "Microsoft Office LTSC for Mac 2024", "versions": [{"version": "16.0.0", "lessThan": "16.109.26051019", "versionType": "custom", "status": "affected"}]}, {"vendor": "Microsoft", "product": "Microsoft Word 2016", "platforms": ["32-bit Systems", "x64-based Systems"], "versions": [{"version": "16.0.1", "lessThan": "16.0.5552.1000", "versionType": "custom", "status": "affected"}]}], "descriptions": [{"value": "Use after free in Microsoft Office Word allows an unauthorized attacker to execute code locally.", "lang": "en-US"}], "problemTypes": [{"descriptions": [{"description": "CWE-416: Use After Free", "lang": "en-US", "type": "CWE", "cweId": "CWE-416"}]}], "providerMetadata": {"orgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8", "shortName": "microsoft", "dateUpdated": "2026-05-12T17:53:38.292Z"}, "references": [{"name": "Microsoft Word Remote Code Execution Vulnerability", "tags": ["vendor-advisory", "patch"], "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40366"}], "metrics": [{"format": "CVSS", "scenarios": [{"lang": "en-US", "value": "GENERAL"}], "cvssV3_1": {"version": "3.1", "baseSeverity": "HIGH", "baseScore": 8.4, "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C"}}]}}}

{}

{"cveTags": [], "descriptions": [{"lang": "en", "value": "Use after free in Microsoft Office Word allows an unauthorized attacker to execute code locally."}], "id": "CVE-2026-40366", "lastModified": "2026-05-12T18:17:15.610", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 8.4, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 2.5, "impactScore": 5.9, "source": "secure@microsoft.com", "type": "Primary"}]}, "published": "2026-05-12T18:17:15.610", "references": [{"source": "secure@microsoft.com", "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40366"}], "sourceIdentifier": "secure@microsoft.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-416"}], "source": "secure@microsoft.com", "type": "Primary"}]}

{}

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