CVE-2026-97755 Microsoft CVE debrief

Who should care

Defenders responsible for Microsoft Office Excel deployments should assess exposure and prioritize patching vulnerable versions, especially those managing Microsoft 365 Apps for Enterprise, Microsoft Office 365 for Mac, Microsoft Office LTSC 2021, Microsoft Office LTSC 2024, Microsoft Office LTSC for Mac 2021, and Microsoft Office LTSC for Mac 2024.

Why it matters

CVE-2026-97755 is a HIGH severity vulnerability in Microsoft Office Excel that allows unauthorized attackers to execute code over a network. Defenders should prioritize patching vulnerable versions and verify exposure across their environments.

• Verify patch deployment for vulnerable Microsoft Office Excel versions
• Assess exposure across environments
• Monitor for suspicious activity

Technical summary

The vulnerability is caused by an out-of-bounds read in Microsoft Office Excel, allowing unauthorized attackers to execute code over a network. Affected products include Microsoft 365 Apps for Enterprise, Microsoft Office 365 for Mac, Microsoft Office LTSC 2021, Microsoft Office LTSC 2024, Microsoft Office LTSC for Mac 2021, Microsoft Office LTSC for Mac 2024, Microsoft SharePoint Server Subscription Edition, and Office Online Server.

Defensive priority

Defenders should prioritize patching vulnerable Microsoft Office Excel versions and verify exposure across their environments.

Recommended defensive actions

• Patch vulnerable Microsoft Office Excel versions
• Verify exposure across environments
• Monitor for suspicious activity

Evidence notes

The CVE record and source item provide details on the vulnerability, affected products, and references to vendor advisories. The vulnerability is caused by an out-of-bounds read in Microsoft Office Excel, allowing unauthorized attackers to execute code over a network. Affected products include Microsoft 365 Apps for Enterprise, Microsoft Office 365 for Mac, Microsoft Office LTSC 2021, Microsoft Office LTSC 2024, Microsoft Office LTSC for Mac 2021, Microsoft Office LTSC for Mac 2024,

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.