Risk Letters

Exploited vulnerability

CVE-2026-45498

TLP:CLEAR

Microsoft Defender Denial of Service Vulnerability

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

Facts

  • Vendor: Microsoft
  • Product: Defender
  • CVSS: 4
  • EPSS (probability of exploitation within 30 days): 63.1 %
  • On CISA's Known Exploited Vulnerabilities list since: 20 May 2026
  • First known exploitation: 20 May 2026
  • CISA's deadline for US federal agencies: 3 June 2026
  • First seen by Risk Letters: 20 May 2026

Members see which Nordic sectors the flaw hits, and what to do about it.

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Data: NVD (public domain), CISA KEV, FIRST EPSS, MITRE ATT&CK, AlienVault OTX. NVD