CVE-2026-64905 Microsoft CVE debrief

Who should care

Defenders responsible for Microsoft Office installations, particularly those using Microsoft 365 Apps for Enterprise, Microsoft Office 2019, and Microsoft Word 2016, should assess exposure and prioritize patching.

Why it matters

CVE-2026-64905 is a high-severity vulnerability in Microsoft Office Word that allows local code execution. Defenders should prioritize patching vulnerable installations to prevent exploitation.

• Local code execution via buffer over-read
• Potential for unauthorized access to sensitive data
• Need for patching vulnerable Microsoft Office installations

Technical summary

The vulnerability is caused by a buffer over-read in Microsoft Office Word, allowing an unauthorized attacker to execute code locally. This issue affects Microsoft Office installations, particularly those using Microsoft 365 Apps for Enterprise, Microsoft Office 2019, and Microsoft Word 2016. The vulnerability has a high CVSS score of 7.8 and is classified as HIGH severity. Defenders should prioritize patching vulnerable Microsoft Office installations to prevent local code execution.

Defensive priority

Defenders should prioritize patching vulnerable Microsoft Office installations to prevent local code execution.

Recommended defensive actions

• Patch vulnerable Microsoft Office installations
• Inventory and verify Microsoft Office versions
• Monitor for suspicious activity

Evidence notes

The CVE record and source item provide details on the vulnerability, but limited information is available on exploitation or impact. Defenders should verify the affected scope, severity, and vendor guidance through official advisories or CVE records. The vulnerability has a high CVSS score of 7.8 and is classified as HIGH severity. There is no information on known or unknown affected scope, but defenders should review compensating controls for exposed systems while remediation is and

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.