CVE-2026-45498
MediumActively exploited (CISA KEV)
Description
Microsoft Defender Denial of Service Vulnerability
SeverityMedium
CVSS4.0
Exploit probability—
Product
Microsoft Defender
PublishedMay 20, 2026
First seenMay 20, 2026
Added to KEVMay 20, 2026
Weakness typeCWE-400Uncontrolled resource consumption
How to fix
CISA required action
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
CISA due date: Jun 3, 2026Update
- microsoft defender_antimalware_platform4.18.26040.7 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| microsoft defender_antimalware_platform | v < 4.18.26040.7 | 4.18.26040.7 |
Check your version
Choose the product and enter the version you run to see whether it falls in the affected range.
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