CVE-2026-64920 Microsoft CVE debrief

Who should care

Defenders responsible for Microsoft Office and Microsoft 365 Apps for Enterprise deployments should assess exposure and prioritize patching vulnerable versions.

Why it matters

CVE-2026-64920 allows unauthorized attackers to execute code locally via a heap-based buffer overflow in Microsoft Office Access, affecting multiple Microsoft Office and Microsoft 365 Apps for Enterprise versions. Defenders should prioritize patching and verifying vendor-provided updates.

• Potential local code execution by unauthorized attackers
• Requires patching vulnerable Microsoft Office and Microsoft 365 Apps for Enterprise versions
• Verification of vendor-provided updates and inventory of deployments is necessary

Technical summary

A heap-based buffer overflow in Microsoft Office Access allows an unauthorized attacker to execute code locally. The vulnerability affects multiple versions of Microsoft Office and Microsoft 365 Apps for Enterprise. This vulnerability can lead to potential local code execution by unauthorized attackers. Defenders should prioritize patching vulnerable Microsoft Office and Microsoft 365 Apps for Enterprise versions to prevent potential local code execution.

Defensive priority

Defenders should prioritize patching vulnerable Microsoft Office and Microsoft 365 Apps for Enterprise versions to prevent potential local code execution.

Recommended defensive actions

• Patch vulnerable Microsoft Office and Microsoft 365 Apps for Enterprise versions
• Verify and apply vendor-provided updates
• Inventory and assess exposure of Microsoft Access and Microsoft 365 Apps for Enterprise deployments

Evidence notes

The CVE record and source item provide details on the vulnerability, but do not specify exploitation or impact. Vendor advisory is available. There is no information on known or confirmed affected deployments. Defenders should verify vendor-provided updates and assess exposure of Microsoft Access and Microsoft 365 Apps for Enterprise deployments.

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.