CVE-2026-64909: Microsoft Office Remote Code Execution Vulnerability
Integer underflow (wrap or wraparound) in Microsoft Office allows an unauthorized attacker to execute code locally.
Other sources
Microsoft Office Remote Code Execution Vulnerability
— Microsoft
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 16.112.26081010 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 16.0.5565.1001Patch KB5002897 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in https://aka.ms/OfficeSecurityReleases
Event History
Frequently Asked Questions
What is the severity of CVE-2026-64909?
CVE-2026-64909 has a severity score of 7.8, categorized as high.
What type of vulnerability is CVE-2026-64909?
CVE-2026-64909 is an integer underflow vulnerability in Microsoft Office that allows for remote code execution.
How do I fix CVE-2026-64909?
To fix CVE-2026-64909, ensure that all affected versions of Microsoft Office are updated to the latest security patches provided by Microsoft.
Which Microsoft Office versions are affected by CVE-2026-64909?
CVE-2026-64909 affects Microsoft Office 2016, Microsoft 365 Apps for Enterprise, and several editions of Microsoft Office LTSC for Mac and Windows.
What could be the impact of CVE-2026-64909 if exploited?
If exploited, CVE-2026-64909 could allow an unauthorized attacker to execute code locally on the victim's machine.