CVE-2026-44817: CWE-843: Access of Resource Using Incompatible Type ('Type Confusion') in Microsoft Microsoft 365 Apps for Enterprise
CVE-2026-44817 is a high-severity vulnerability in Microsoft 365 Apps for Enterprise, specifically in Microsoft Office Excel. It involves an integer underflow condition that can lead to type confusion, allowing an unauthorized attacker to execute code locally. The vulnerability affects version 16. 0. 1. An official fix is available from Microsoft, and the product is a cloud service with vendor-managed remediation.
AI Analysis
Technical Summary
This vulnerability (CVE-2026-44817) is classified as CWE-843 (Access of Resource Using Incompatible Type, or Type Confusion) and arises from an integer underflow in Microsoft Office Excel within Microsoft 365 Apps for Enterprise. The flaw allows an attacker to execute code locally without privileges but requires user interaction. The CVSS v3.1 base score is 7.8, indicating high severity, with impact on confidentiality, integrity, and availability. Microsoft has published an official fix and manages remediation for this cloud-hosted service. The affected version explicitly stated is 16.0.1.
Potential Impact
Successful exploitation can lead to local code execution by an unauthorized attacker, impacting confidentiality, integrity, and availability of the affected system. The vulnerability requires user interaction but no privileges. There are no known exploits in the wild at this time.
Mitigation Recommendations
An official fix is available from Microsoft. Since this is a cloud service, Microsoft manages remediation server-side. Users and administrators should ensure their Microsoft 365 Apps for Enterprise are updated to the fixed version as per Microsoft's advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-44817.
CVE-2026-44817: CWE-843: Access of Resource Using Incompatible Type ('Type Confusion') in Microsoft Microsoft 365 Apps for Enterprise
Description
CVE-2026-44817 is a high-severity vulnerability in Microsoft 365 Apps for Enterprise, specifically in Microsoft Office Excel. It involves an integer underflow condition that can lead to type confusion, allowing an unauthorized attacker to execute code locally. The vulnerability affects version 16. 0. 1. An official fix is available from Microsoft, and the product is a cloud service with vendor-managed remediation.
CVSS v3.1
Score 7.8high
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability (CVE-2026-44817) is classified as CWE-843 (Access of Resource Using Incompatible Type, or Type Confusion) and arises from an integer underflow in Microsoft Office Excel within Microsoft 365 Apps for Enterprise. The flaw allows an attacker to execute code locally without privileges but requires user interaction. The CVSS v3.1 base score is 7.8, indicating high severity, with impact on confidentiality, integrity, and availability. Microsoft has published an official fix and manages remediation for this cloud-hosted service. The affected version explicitly stated is 16.0.1.
Potential Impact
Successful exploitation can lead to local code execution by an unauthorized attacker, impacting confidentiality, integrity, and availability of the affected system. The vulnerability requires user interaction but no privileges. There are no known exploits in the wild at this time.
Mitigation Recommendations
An official fix is available from Microsoft. Since this is a cloud service, Microsoft manages remediation server-side. Users and administrators should ensure their Microsoft 365 Apps for Enterprise are updated to the fixed version as per Microsoft's advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-44817.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- microsoft
- Date Reserved
- 2026-05-07T20:07:18.271Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- official-fix
- Is Cloud Service
- true
- Vendor Advisory Urls
- [{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-44817","vendor":"Microsoft"}]
Threat ID: 6a284cd18dd33fbd85664a93
Added to database: 6/9/2026, 5:26:41 PM
Last enriched: 6/9/2026, 10:41:29 PM
Last updated: 6/10/2026, 4:56:23 AM
Views: 3
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