Vulnerability intelligence
CVE-2026-45498
Microsoft Defender Denial of Service Vulnerability
Microsoft Defender Denial of Service Vulnerability
CVSS Score
4
Medium
EPSS — Exploit Probability
3.5%
Riskier than 88% of all CVEs
Exploitation
Confirmed in the wild
Used in ransomware campaigns
Remediation
Patch available
Federal deadline 2026-06-03
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. Deadline for federal agencies: 2026-06-03.
4 articles across 4 outlets · first covered May 20, 2026 · latest May 21, 2026
Coverage timeline
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Microsoft Defender vulnerabilities are being exploited in the wildwww.malwarebytes.com · May 21, 2026
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Microsoft fixes two zero day Defender bugs under active attackwww.securityweek.com · May 21, 2026
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CISA adds CVE-2026-45498 to KEV, urges Defender patch by Junewww.cisa.gov · May 20, 2026
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CISA Adds Microsoft Defender DoS Flaw CVE-2026-45498 to KEV Listcisa.gov · May 20, 2026