What’s Vulnerable › Vulnerabilities

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

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: yes — in CISA KEV since 2026-05-20
• EPSS: 63.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-05-20 · updated 2026-08-10
• Weakness: CWE-400

Description

Microsoft Defender Denial of Service Vulnerability

Affected products

• Microsoft Defender Antimalware Platform: before 4.18.26040.7 — fixed in 4.18.26040.7
• Microsoft Defender Antimalware Platform: from 4.0.0.0 before 4.18.26040.7 — fixed in 4.18.26040.7

How to fix

Upgrade to a fixed version: Microsoft Defender Antimalware Platform 4.18.26040.7; Microsoft Defender Antimalware Platform 4.18.26040.7. Check the vendor advisory for mitigations.

References

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-45498
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-45498

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