Microsoft Office Remote Code Execution VulnerabilityVendor advisorypatch
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-64909 CVE-2026-64909
HIGH
Microsoft Office Remote Code Execution Vulnerability
Record summary
CVE-2026-64909 has a selected CVSS score of 7.8 (high).
Description
Integer underflow (wrap or wraparound) in Microsoft Office allows an unauthorized attacker to execute code locally.
Description source: GitHub Advisory
Exploitation context
CISA SSVC decision
ExploitationNone
AutomatableNo
Technical impactTotal
CISA Coordinator · SSVC 2.0.3 · Evaluated Aug 6, 2026 · Source: CVE List
Affected products and versions
8| Product | Source | Version range | Status |
|---|---|---|---|
Microsoft 365 Apps for EnterpriseBrowse Microsoft / Microsoft 365 Apps for Enterprise | CVE List | 16.0.1 to < https://aka.ms/OfficeSecurityReleases | affected |
Microsoft Office 2016Browse Microsoft / Microsoft Office 2016 | CVE List | 16.0.0 to < 16.0.5565.1001 | affected |
Microsoft Office 2019Browse Microsoft / Microsoft Office 2019 | CVE List | 19.0.0 to < https://aka.ms/OfficeSecurityReleases | affected |
Microsoft Office 365 for MacBrowse Microsoft / Microsoft Office 365 for Mac | CVE List | 1.0.0 to < 16.112.26081010 | affected |
Microsoft Office LTSC 2021Browse Microsoft / Microsoft Office LTSC 2021 | CVE List | 16.0.1 to < https://aka.ms/OfficeSecurityReleases | affected |
Microsoft Office LTSC 2024Browse Microsoft / Microsoft Office LTSC 2024 | CVE List | 16.0.0 to < https://aka.ms/OfficeSecurityReleases | affected |
Microsoft Office LTSC for Mac 2021Browse Microsoft / Microsoft Office LTSC for Mac 2021 | CVE List | 16.0.1 to < 16.112.26081010 | affected |
Microsoft Office LTSC for Mac 2024Browse Microsoft / Microsoft Office LTSC for Mac 2024 | CVE List | 16.0.0 to < 16.112.26081010 | affected |
References
2nvd.nist.gov
https://nvd.nist.gov/vuln/detail/CVE-2026-64909