CVE-2026-20957: CWE-191: Integer Underflow (Wrap or Wraparound) in Microsoft Microsoft 365 Apps for Enterprise
Integer underflow (wrap or wraparound) in Microsoft Office Excel allows an unauthorized attacker to execute code locally.
AI Analysis
Technical Summary
This vulnerability involves an integer underflow (wrap or wraparound) in Microsoft Office Excel, part of Microsoft 365 Apps for Enterprise version 16.0.1. Exploitation could allow an attacker to execute arbitrary code locally without privileges and with user interaction. The CVSS 3.1 vector indicates low attack complexity, no privileges required, but user interaction is needed. Confidentiality, integrity, and availability impacts are all high. The vulnerability has been officially published and a patch is available.
Potential Impact
Successful exploitation could result in local code execution by an unauthorized attacker, potentially leading to full compromise of the affected system's confidentiality, integrity, and availability. The attack requires user interaction but no prior privileges. There are no known exploits in the wild currently.
Mitigation Recommendations
A patch is available for this vulnerability. It is recommended to apply the official update from Microsoft for Microsoft 365 Apps for Enterprise version 16.0.1 to remediate this issue. Since this is not a cloud service, remediation depends on applying the patch to affected installations.
CVE-2026-20957: CWE-191: Integer Underflow (Wrap or Wraparound) in Microsoft Microsoft 365 Apps for Enterprise
Description
Integer underflow (wrap or wraparound) in Microsoft Office Excel allows an unauthorized attacker to execute code locally.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability involves an integer underflow (wrap or wraparound) in Microsoft Office Excel, part of Microsoft 365 Apps for Enterprise version 16.0.1. Exploitation could allow an attacker to execute arbitrary code locally without privileges and with user interaction. The CVSS 3.1 vector indicates low attack complexity, no privileges required, but user interaction is needed. Confidentiality, integrity, and availability impacts are all high. The vulnerability has been officially published and a patch is available.
Potential Impact
Successful exploitation could result in local code execution by an unauthorized attacker, potentially leading to full compromise of the affected system's confidentiality, integrity, and availability. The attack requires user interaction but no prior privileges. There are no known exploits in the wild currently.
Mitigation Recommendations
A patch is available for this vulnerability. It is recommended to apply the official update from Microsoft for Microsoft 365 Apps for Enterprise version 16.0.1 to remediate this issue. Since this is not a cloud service, remediation depends on applying the patch to affected installations.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- microsoft
- Date Reserved
- 2025-12-04T20:04:16.340Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 69668ae6a60475309f9ae262
Added to database: 1/13/2026, 6:11:50 PM
Last enriched: 4/3/2026, 12:52:51 PM
Last updated: 5/10/2026, 9:13:42 AM
Views: 261
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