CVE-2026-45498: Microsoft Defender Denial of Service Vulnerability

High severity, CVSS 7.5. Actively exploited: in CISA KEV since 2026-05-20. EPSS: 1.3% chance of exploitation in the next 30 days.

Microsoft Defender Denial of Service Vulnerability

Affected products

• Microsoft Defender Antimalware Platform: before 4.18.26040.7 (fixed in 4.18.26040.7)

Published 2026-05-20. Last modified 2026-07-23.