Exploited CVEs / Microsoft / CVE-2026-45498
CVE-2026-45498
Microsoft Defender Denial of Service Vulnerability. Exploitation in the wild is confirmed by CISA, not predicted. Federal agencies were required to remediate by 2026-06-03 (that deadline has passed); treat that date as the outer bound for your own environment. The fix is in the vendor advisory: Microsoft Security Update Guide (MSRC), linked below.
Actively exploited Microsoft Defender vulnerability. Added to the CISA KEV catalog 2026-05-20.
Risk summary
Updated July 25, 2026. Data refreshed on every build from MSRC, CISA KEV, and FIRST EPSS.
Senserva AI Opinion for CVE-2026-45498
Attackers are exploiting a denial of service flaw in the Microsoft Defender Antimalware Platform itself, per its May 20, 2026 CISA KEV entry, and the goal of such attacks is obvious: crash the AV engine so the real payload runs unscanned. The CVSS score is only 4.0 and the Severity rating Medium, but a bug that switches off your endpoint protection has impact far beyond its score. Every environment relying on Defender is in the audience for this one.
Do this: Verify the Defender antimalware platform version is current across the fleet and alert on Defender service crashes or unexpected protection-state changes.
AI-generated from public data, 2026-07-07. Verify against the vendor advisory before acting.
Senserva AI Opinion and rich prompt for CVE-2026-45498
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Full tracking and change history for CVE-2026-45498
Published and last-revised dates are authoritative, from Microsoft MSRC (or the CISA KEV date-added). Senserva additionally records day-to-day changes from 2026-07-07, refreshed several times a day; the change count reflects that forward-only tracking.
CISA required action
Federal (BOD 22-01) remediation due date: 2026-06-03 (past due).
Official fix for CVE-2026-45498
The authoritative fix and affected-version list are published by the vendor. Find the Defender advisory on Microsoft Security Update Guide (MSRC).
Common questions about CVE-2026-45498
Is CVE-2026-45498 actively exploited?
Yes. CVE-2026-45498 was added to the CISA Known Exploited Vulnerabilities (KEV) catalog on 2026-05-20, which means exploitation in the wild has been confirmed, not predicted.
What is the CISA deadline and required action for CVE-2026-45498?
CISA set the federal (BOD 22-01) remediation due date at 2026-06-03, which has passed; treat any unremediated system as overdue.
What fixes CVE-2026-45498?
The authoritative fix is in the vendor advisory: see Microsoft Security Update Guide (MSRC) for the patched Defender versions and any workarounds. KEV listing makes this a fix-first item: patch it ahead of higher-CVSS issues nobody is exploiting.
Can I ask my own AI about CVE-2026-45498?
Yes. This page includes a free, ready-to-paste AI prompt containing CVE-2026-45498's key facts: severity, CVSS, EPSS, the KEV date, the CISA due date, and the required action. Copy it into Claude, ChatGPT, or Copilot; the data is refreshed twice a day (5 AM and 3 PM US Central).
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Authoritative references
Every actively exploited CVE, searchable with due dates and CSV export: the exploited-CVE tracker. The newest additions: exploited this week.
