CVE-2026-45498 Microsoft CVE debrief

Who should care

Defenders responsible for Microsoft Defender deployments should assess exposure and apply mitigations according to vendor instructions. This includes verifying exposure of Microsoft Defender to this denial of service vulnerability and applying mitigations per vendor instructions. Additionally, defenders should follow applicable BOD 22-01 guidance for cloud services to ensure compliance.

Why it matters

Defenders should prioritize verifying exposure and applying mitigations to prevent potential denial of service in Microsoft Defender deployments.

• Verify exposure of Microsoft Defender deployments to this denial of service vulnerability
• Apply mitigations per vendor instructions to prevent potential denial of service
• Follow applicable BOD 22-01 guidance for cloud services to ensure compliance

Technical summary

A denial of service vulnerability exists in Microsoft Defender. This vulnerability could allow an attacker to cause a denial of service condition in Microsoft Defender deployments. The vulnerability is listed in the CISA Known Exploited Vulnerabilities catalog, indicating that it is known to be exploited in the wild. Defenders should prioritize verifying exposure and applying mitigations to prevent potential denial of service.

Defensive priority

Defenders should prioritize verifying exposure and applying mitigations.

Recommended defensive actions

• Verify exposure of Microsoft Defender to this denial of service vulnerability
• Apply mitigations per vendor instructions
• Follow applicable BOD 22-01 guidance for cloud services

Evidence notes

The CISA Known Exploited Vulnerabilities catalog lists this vulnerability as known to be exploited in the wild. The vulnerability affects Microsoft Defender deployments. There is no information on the specific conditions or vectors required for exploitation. Defenders should verify exposure and apply mitigations according to vendor instructions. The CVE record was published on 2026-05-20T00:00:00.000Z and has not been modified since then.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.