MicrosoftCVE-2026-64909
Microsoft Office: integer overflow
High7.8CVE-2026-64909 · Published Aug 11, 2026 · updated Aug 14, 2026
Integer underflow (wrap or wraparound) in Microsoft Office allows an unauthorized attacker to execute code locally.
Affected versions
| Package | Affected | Fixed in |
|---|---|---|
| Microsoft 365 Apps for Enterprise Product | >= 16.0.1, < https://aka.ms/OfficeSecurityReleases | https://aka.ms/OfficeSecurityReleases |
| Microsoft Office 2016 Product | >= 16.0.0, < 16.0.5565.1001 | 16.0.5565.1001 |
| Microsoft Office 2019 Product | >= 19.0.0, < https://aka.ms/OfficeSecurityReleases | https://aka.ms/OfficeSecurityReleases |
| Microsoft Office 365 for Mac Product | >= 1.0.0, < 16.112.26081010 | 16.112.26081010 |
| Microsoft Office LTSC 2021 Product | >= 16.0.1, < https://aka.ms/OfficeSecurityReleases | https://aka.ms/OfficeSecurityReleases |
| Microsoft Office LTSC 2024 Product | >= 16.0.0, < https://aka.ms/OfficeSecurityReleases | https://aka.ms/OfficeSecurityReleases |
| Microsoft Office LTSC for Mac 2021 Product | >= 16.0.1, < 16.112.26081010 | 16.112.26081010 |
| Microsoft Office LTSC for Mac 2024 Product | >= 16.0.0, < 16.112.26081010 | 16.112.26081010 |
Details and references
More Microsoft advisories
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|---|---|---|---|
| Aug 11 | Copilot Chat Security Feature Bypass Vulnerability | High7.1 | 1.132.1 |
| Aug 11 | Copilot Custom Agent Hook Remote Code Execution Vulnerability | High7.8 | 1.132.1 |
| Aug 11 | Information disclosure vulnerability | Medium | 1.132.1 |
| Aug 11 | Fileless RCE in VS Code Web Remote Terminal via URL-Controlled NODE_OPTIONS | High8.8 | 1.132.1 |
| Aug 11 | Visual Studio Code web deployments - environmentService.ts - RCE via NODE_OPTIONS --import from URL payload | High8.8 | 1.132.1 |
| Aug 11 | TerminalInstance._createProcess - Workspace Trust bypass via terminal waitOnExit | High7.8 | 1.132.1 |