CVE-2026-77902 Advisory
Severity: HIGH (CVSS 8.8)
Affected Product:
- Microsoft Defender Business
Vulnerability Description: Heap-based buffer overflow in Microsoft Office Excel allows remote code execution via network attack.
KEV Status: Not currently exploited in the wild
Remediation: Apply security updates from Microsoft. Reference: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-77902
Recommendation: Prioritize patching due to HIGH severity and remote attack vector.