CVE-2026-45498: Microsoft Defender Denial of Service Vulnerability
Published May 19, 2026
·Updated
Microsoft Defender contains an unspecified vulnerability that allows for denial of service.
Other sources
Microsoft Defender Denial of Service Vulnerability
— Microsoft
Affected Software
4 affected componentsFixes available
Microsoft Defender
Microsoft Defender Antimalware Platform
Microsoft Defender Antimalware Platform<4.18.26040.7
Microsoft Defender Antimalware Platform<4.18.26040.7
4.18.26040.7
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 4.18.26040.7
Event History
May 19, 2026
CVE Published
via Microsoft·02:00 PM
Known Exploited
via Microsoft·02:00 PM
Data Sourced
via Microsoft·02:00 PM
DescriptionSeverityWeakness
Data Sourced
via Microsoft·02:00 PM
Affected Software
Updated
via Microsoft·02:00 PM
Description
Updated
via Microsoft·02:00 PM
DescriptionWeakness
May 20, 2026
Data Sourced
via CISA·12:00 AM
RemedyDescriptionAffected Software
CVE Published
via MITRE·01:09 PM
Data Sourced
via MITRE·01:09 PM
DescriptionSeverity
Data Sourced
via NVD·01:16 PM
DescriptionSeverityWeaknessAffected Software
May 21, 2026
News Published
via BleepingComputer·07:49 AM
News Published
via BleepingComputer·07:50 AM
Frequently Asked Questions
1
What is the severity of CVE-2026-45498?
CVE-2026-45498 has a severity rating of 7.5, classified as high.
2
What type of vulnerability is CVE-2026-45498?
CVE-2026-45498 is a denial of service vulnerability affecting Microsoft Defender.
3
How do I fix CVE-2026-45498?
To fix CVE-2026-45498, apply the mitigations as per vendor instructions, or discontinue use of the affected product if unable to implement the mitigations.
4
Is CVE-2026-45498 actively exploited?
Yes, CVE-2026-45498 is listed as exploited in the wild.
5
Which software is affected by CVE-2026-45498?
CVE-2026-45498 affects the Microsoft Defender Antimalware Platform and Microsoft Defender.