CVE-2026-108446 Microsoft CVE debrief

Who should care

Defenders responsible for Microsoft Office Excel deployments, network administrators, and incident response teams should assess exposure and prioritize verification and potential remediation.

Why it matters

CVE-2026-108446 is a high-severity use-after-free vulnerability in Microsoft Office Excel that allows unauthorized attackers to execute code over a network. Defenders should verify and assess exposure, prioritize remediation, and update incident response plans.

• Potential code execution over a network requires verification of Excel configurations and network access controls
• Unauthorized attackers may exploit this vulnerability to execute malicious code
• Defenders should prioritize verifying and updating incident response plans for potential code execution attacks

Technical summary

CVE-2026-108446 is a use-after-free vulnerability in Microsoft Office Excel that allows an unauthorized attacker to execute code over a network. The vulnerability has a CVSS score of 8.8 and is classified as HIGH severity. This vulnerability affects Microsoft Office Excel deployments, and defenders should verify and assess exposure to prioritize remediation and update incident response plans for potential code execution attacks.

Defensive priority

Verify and assess exposure to Microsoft Office Excel vulnerability

Recommended defensive actions

• Verify Microsoft Office Excel versions and configurations for potential exposure
• Assess network access controls and restrictions for Excel services
• Review and update incident response plans for potential code execution attacks

Evidence notes

CVE Program and NVD records indicate a use-after-free vulnerability in Microsoft Office Excel, allowing unauthorized attackers to execute code over a network.

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.