CVE-2026-40366

Access of resource using incompatible type ('type confusion') in Microsoft Office Word allows an unauthorized attacker to execute code locally.

CVSS v3 8.4 HIGH

8.4^/10

CVSS v3 : HIGH

Vector :

Exploitability : 2.5 / Impact : 5.9

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40366	Vendor Advisory

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:microsoft:365_apps:-::::enterprise::x64:*
	cpe:2.3:a:microsoft:365_apps:-::::enterprise::x86:*
	cpe:2.3:a:microsoft:office:2019::::::x64:
	cpe:2.3:a:microsoft:office:2019::::::x86:
	cpe:2.3:a:microsoft:office_long_term_servicing_channel:2021:::::-:x64:*
	cpe:2.3:a:microsoft:office_long_term_servicing_channel:2021:::::-:x86:*
	cpe:2.3:a:microsoft:office_long_term_servicing_channel:2021:::::macos::
	cpe:2.3:a:microsoft:office_long_term_servicing_channel:2024:::::-:x64:*
	cpe:2.3:a:microsoft:office_long_term_servicing_channel:2024:::::-:x86:*
	cpe:2.3:a:microsoft:office_long_term_servicing_channel:2024:::::macos::
	cpe:2.3:a:microsoft:word:2016::::::x64:
	cpe:2.3:a:microsoft:word:2016::::::x86:

History

No history.

Information

Published : 2026-05-12 18:17

Updated : 2026-06-17 10:45

NVD link : CVE-2026-40366

Mitre link : CVE-2026-40366

CVE.ORG link : CVE-2026-40366

JSON object : View

Products Affected

microsoft

office_long_term_servicing_channel
office
365_apps
word

CWE

CWE-416

Use After Free

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"version": "16.0.1", "lessThan": "https://aka.ms/OfficeSecurityReleases", "versionType": "custom"}], "platforms": ["32-bit Systems", "x64-based Systems"]}, {"vendor": "Microsoft", "product": "Microsoft Office 2019", "versions": [{"status": "affected", "version": "19.0.0", "lessThan": "https://aka.ms/OfficeSecurityReleases", "versionType": "custom"}], "platforms": ["32-bit Systems", "x64-based Systems"]}, {"vendor": "Microsoft", "product": "Microsoft Office LTSC 2021", "versions": [{"status": "affected", "version": "16.0.1", "lessThan": "https://aka.ms/OfficeSecurityReleases", "versionType": "custom"}], "platforms": ["32-bit Systems", "x64-based Systems"]}, {"vendor": "Microsoft", "product": "Microsoft Office LTSC 2024", "versions": [{"status": "affected", "version": "16.0.0", "lessThan": "https://aka.ms/OfficeSecurityReleases", "versionType": "custom"}], "platforms": ["32-bit Systems", "x64-based Systems"]}, {"vendor": "Microsoft", "product": "Microsoft Office LTSC for Mac 2021", "versions": [{"status": "affected", "version": "16.0.1", "lessThan": "16.109.26051019", "versionType": "custom"}]}, {"vendor": "Microsoft", "product": "Microsoft Office LTSC for Mac 2024", "versions": [{"status": "affected", "version": "16.0.0", "lessThan": "16.109.26051019", "versionType": "custom"}]}, {"vendor": "Microsoft", "product": "Microsoft Word 2016", "versions": [{"status": "affected", "version": "16.0.1", "lessThan": "16.0.5552.1000", "versionType": "custom"}], "platforms": ["32-bit Systems", "x64-based Systems"]}]}], "published": "2026-05-12T18:17:15.610", "references": [{"url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40366", "tags": ["Vendor Advisory"], "source": "secure@microsoft.com"}], "vulnStatus": "Modified", "weaknesses": [{"type": "Secondary", "source": "secure@microsoft.com", "description": [{"lang": "en", "value": "CWE-416"}]}], "descriptions": [{"lang": "en", "value": "Access of resource using incompatible type ('type confusion') in 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