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CISA KEV·Added 2026-05-20 — agencies required to remediate by 2026-06-03

CVE-2026-45498

MEDIUM

Microsoft Defender Denial of Service Vulnerability

Published
May 20, 2026
Updated
Jul 23, 2026
Affected
0 pkgs
Patched
None yet
Exploits
None indexed

EPSS Exploitation Probability

via FIRST.org ↗
63.1%probability of exploitation in next 30 days
High Risk99th percentile0.00%
0.00%26.9%53.8%80.8%4.1%63.1%63.1%Jun 26Jul 26Jul 26

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Description

Microsoft Defender Denial of Service Vulnerability

Affected Products

1 product · 1 configurations
Application
defender antimalware platformmicrosoft
< 4.18.26040.7
range

Detection & mitigation playbook

Vendor / appliance
  1. Detect

    Inventory every microsoft defender antimalware platform deployment and check each version against the affected-products list above. Because the exploit targets the running system rather than your application code, also watch for exploitation at the network and runtime layer — O3 flags the exploit behaviour from runtime telemetry and egress traffic even before a vulnerable build is confirmed.

  2. Fix

    Apply the microsoft defender antimalware platform security patch or hotfix for CVE-2026-45498 on the affected version, following the vendor advisory for your exact build.

  3. Workarounds

    Cut exposure now: restrict the management/admin interface to trusted networks, segment the device, and apply the vendor's recommended configuration mitigations and any WAF/IPS signature. O3's runtime protection blocks the exploit chain at execution, holding the line on unpatched or end-of-life systems until you can patch.

  4. How O3 protects you

    O3 detects and blocks CVE-2026-45498 exploitation at runtime: eBPF exploit-chain detection, plus L7 egress monitoring that catches the post-exploitation callback and severs the attacker's outbound channel.

Tailored to CVE-2026-45498. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

Microsoft Defender Denial of Service Vulnerability
O3 Security · Runtime Protection

Is CVE-2026-45498 being exploited in your environment?

O3's eBPF runtime sensors and L7 egress monitoring detect and block the CVE-2026-45498 exploit chain at execution — protecting unpatched and end-of-life systems until the vendor patch is applied.