Actively exploited
Listed in CISA’s Known Exploited Vulnerabilities catalog since May 20, 2026.
CVE-2026-45498
Microsoft Defender Denial of Service Vulnerability
Added to KEV May 20, 2026
Alert details
- Source feed
- CISA KEV
- CVE ID
- CVE-2026-45498
- Affected products
- Defender · Microsoft Defender · Microsoft
What happened
Microsoft Defender contains an unspecified vulnerability that allows for denial of service.
What it means for your business
Microsoft Defender is listed in CISA's Known Exploited Vulnerabilities catalog (CVE-2026-45498). Microsoft Defender contains an unspecified vulnerability that allows for denial of service. CISA remediation due date: 2026-06-03. If you need help checking exposure, call (864) 335-9223.
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: June 3, 2026
Sources
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