CVE-2026-81386 Advisory
Severity: HIGH (CVSS 7.8)
Affected Product: Microsoft Defender Business
Vulnerability: Heap-based buffer overflow in Microsoft Office Excel allows local code execution.
KEV Status: Not currently listed as exploited in the wild.
Remediation: Apply security updates from Microsoft. See MSRC vulnerability guide: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-81386
Impact: Local attackers may execute arbitrary code with user privileges through specially crafted Excel files.