CVE-2026-78517 Advisory
Severity: HIGH (CVSS 8.8)
KEV Status: Not exploited in the wild
Affected Product: Microsoft Defender Business
Vulnerability: Heap-based buffer overflow in Microsoft Office Word enabling remote code execution.
Remediation: Apply security updates from Microsoft via the official update guide: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-78517
Action Items:
- Prioritize patching Microsoft Defender Business systems
- Monitor for available security updates from Microsoft
- Consider network segmentation for at-risk systems pending patches