Vulnerability · CVE-2026-45498
Microsoft Defender Denial of Service Vulnerability
Published May 19, 2026 · catalog updated Jul 23, 2026 · defender antimalware platform
Patch now
CVE-2026-45498 is in the CISA known-exploited catalog, due Jun 3, 2026. Confirm defender antimalware platform against the vendor advisory and apply that fix. The CVSS score does not change the priority.
Gaps on this record
- No version range is stored. A customer cannot check an installed version against this record.
- Severity
- High7.5
- Known exploitation
- CISA KEV and VulnCheck KEV
- EPSS
- 1.27%
- Remediation
- Remediation guidance
- Affected products
- cpe microsoft/defender antimalware platform · vendor Microsoft Defender
Microsoft Defender contains an unspecified vulnerability that allows for denial of service.
Are you affected?
Enter the version you run. The result uses only the ranges stored on this record.
The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.
- cpe microsoft/defender antimalware platformversion unspecified
- vendor Microsoft Defenderversion unspecified
How to fix CVE-2026-45498
Recommended remediation
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 Jun 3, 2026.
Official advisories
What to do
Three questions, each answered from this record only. Confirm the vendor advisory before you patch.
Should you patch?
CVE-2026-45498 is in the CISA known-exploited catalog, due Jun 3, 2026. Confirm defender antimalware platform against the vendor advisory and apply that fix. The CVSS score does not change the priority.
Which versions are affected?
Affected version ranges are not on this record. Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
What should an analyst verify?
CWE-400: Uncontrolled Resource Consumption. EPSS 1.27%. The CISA KEV listing is the exploitation evidence. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.
Code
The project this record applies to. Exploit listings stay in References.
No public source repository is identified for this product.
Timeline
Detection, updates, and resolution for this record.
May 20, 2026 · Catalog
Detected
Microsoft Defender contains an unspecified vulnerability that allows for denial of service.
May 20, 2026 · CISA KEV
Known exploited
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Jun 3, 2026 · CISA KEV
Remediation due
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Jul 23, 2026 · Catalog
Updated
Microsoft Defender contains an unspecified vulnerability that allows for denial of service.
Jul 23, 2026 · NIST NVD
Updated
Microsoft Defender Denial of Service Vulnerability
Sources
- CISA KEVConfirmed exploitationCVE-2026-45498
Microsoft Defender contains an unspecified vulnerability that allows for denial of service.
cisa.gov - CVE.orgVulnerability recordCVE-2026-45498
Official CVE identifier
cve.org - FIRST EPSSExploitation probabilityCVE-2026-45498
30-day exploitation probability 1.3%
first.org - NIST NVDVulnerability recordCVE-2026-45498
Microsoft Defender Denial of Service Vulnerability
nvd.nist.gov - VulnCheck KEVConfirmed exploitationCVE-2026-45498
Microsoft Defender contains an unspecified vulnerability that allows for denial of service.
vulncheck.com
References
Freshness
Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.