CVE-2026-45498

MEDIUMNVD 4.09.0▲

4.0

Microsoft Defender Denial of Service Vulnerability

CVSS v3: 4.0
EG Score: 9.0(high)
EPSS: 86.2%
KEV: ⚠ Exploited

Published

May 20, 2026

Last Modified

May 20, 2026

References (2)

secure@microsofthttps://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-45498
134c704f-9b21-4f2e-91b3-4a467353bcc0https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-45498

Vendor Advisories for CVE-2026-45498(2)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Frequently asked(6)

What is CVE-2026-45498?

CVE-2026-45498 is a medium vulnerability published on May 20, 2026. Microsoft Defender Denial of Service Vulnerability

When was CVE-2026-45498 disclosed?

CVE-2026-45498 was first published in the National Vulnerability Database on May 20, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2026-45498 actively exploited?

Yes. CISA added CVE-2026-45498 to the Known Exploited Vulnerabilities catalog on May 20, 2026, affecting Microsoft Defender. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate patching attention.

What is the CVSS score of CVE-2026-45498?

CVE-2026-45498 has a CVSS v3 base score of 4.0 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.0.

Which products are affected by CVE-2026-45498?

CVE-2026-45498 affects Microsoft Defender. The full affected-products list, including version ranges and fixed versions, is shown in the Affected Packages section of this page.

How do I remediate CVE-2026-45498?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-45498, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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CVE-2026-45498

📅 Published

🔄 Last Modified

🔗 References (2)

📣 Vendor Advisories for CVE-2026-45498(2)

❓ Frequently asked(6)