In CISA KEV4.0 MediumCWE-400
CVE-2026-45498
Microsoft Defender Denial of Service Vulnerability
MicrosoftDefender
Status
- Exploited in the wild
- In CISA KEV since 20 May
- Vendor fix available
Federal deadlineWed 3 Jun, 23:59 UTC
Passed 143 days ago
CISA KEV · added 20 May
Exploit probabilityEPSSchecked 25 Oct
1.3%probability of exploitation in the next 30 days
Higher than 70% of scored CVEs
SeverityCVSS
4.0Medium
Description NVD
Microsoft Defender Denial of Service Vulnerability
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.
Coverage 4 articles · 3 outlets
See the full timelineShow as table
| Published (UTC) | Outlet | Headline |
|---|---|---|
| Wed 20 May · 19:47 UTC | CISA | CISA Adds Microsoft Defender DoS Flaw CVE-2026-45498 to KEV List |
| Wed 20 May · 20:13 UTC | CISA | CISA adds CVE-2026-45498 to KEV, urges Defender patch by June |
| Thu 21 May · 10:21 UTC | SecurityWeek | Microsoft fixes two zero day Defender bugs under active attack |
| Thu 21 May · 18:41 UTC | Malwarebytes | Microsoft Defender vulnerabilities are being exploited in the wild |
- Microsoft Defender vulnerabilities are being exploited in the wildMalwarebytes · mentions it in passing
- Microsoft fixes two zero day Defender bugs under active attackSecurityWeek · mentions it in passing
- CISA adds CVE-2026-45498 to KEV, urges Defender patch by JuneCISA · official notice
- CISA Adds Microsoft Defender DoS Flaw CVE-2026-45498 to KEV ListCISA · first in our coverage · official notice