CVE-2026-78526 Advisory
Severity: HIGH (CVSS 8.8)
Affected Product:
- Microsoft Defender Business
Vulnerability Type: Heap-based buffer overflow in Microsoft Office Word enabling remote code execution.
KEV Status: Not currently listed on CISA KEV catalog.
Exploited in the Wild: No evidence of active exploitation reported.
Remediation:
- Check Microsoft Security Response Center (MSRC) update guidance at: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-78526
- Apply vendor-supplied patches when available
- Monitor systems for suspicious Office Word activity
Recommendation: Prioritize patching given the network-exploitable nature and HIGH severity rating. Maintain backups and test patches in non-production environments before deployment.