VulnerabilityAnalyzed
CVE-2026-45498
Microsoft Defender Denial of Service Vulnerability
KEVHIGH 7.5EPSS 63.1%
Does this matter?
Known to be exploited in the wild (CISA KEV, CISA remediation deadline 3 June 2026). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.
Description
Microsoft Defender Denial of Service Vulnerability
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 63.08% probability · 99th percentile
- CISA KEV
- Listed 20 May 2026 · due 3 June 2026
- Weakness
- CWE-400
- Affected
- microsoft/defender antimalware platform
- Source
- secure@microsoft.com
CISA notes
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2026-45498 ; https://nvd.nist.gov/vuln/detail/CVE-2026-45498
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-45498Vendor Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-45498Third Party Advisory, US Government Resource
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.