All vulnerabilities
CVE-2026-45498

Microsoft Defender Denial of Service Vulnerability

Microsoft Defender
Open in ThreatlineRecord JSON
CVSS
4.0Medium
ExploitationExploited in the wildAdded to KEV 20 May 2026CISA KEV
Exploit odds (EPSS)1.27%Chance of exploitation activity in the next 30 days, higher than 69% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in4.18.26040.7Fixed versionCVE List
Federal deadline3 Jun 2026Remediation due date for US federal agenciesCISA KEV
CISA required actionApply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. CISA KEV

What fixes it

  • 4.18.26040.7Microsoft Defender Antimalware PlatformCVE List

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

Timeline

  1. 20 May 2026Added to CISA KEVCISA KEV
  2. 20 May 2026, 13:09 UTCPublishedCVE List

Description

Microsoft Defender contains an unspecified vulnerability that allows for denial of service.

Text from CVE List

Affected versions 1

  • Microsoft Defender Antimalware Platformaffected: 4.0.0.0 before 4.18.26040.7CVE List

References 4