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Defender

PRODUCT

· dossier confidence 20%

Microsoft Defender is a critical endpoint protection product with a documented history of severe security failures, including multiple critical and high-severity vulnerabilities that allow attackers to bypass core security controls, escalate privileges, and execute remote code. Recent zero-day exploits have demonstrated that even patched systems can be compromised, posing a significant risk to defense-industrial-base and CMMC-compliant environments.

Failure events
5
Zero-days
0
RCEs
1
On KEV
5
Critical
2
Worst shame
85
PROFILE
CategoryEndpoint Security / AntivirusWhat they doMicrosoft Defender is an endpoint protection platform providing antivirus, anti-malware, and threat protection for Windows operating systems. Websitehttps://www.microsoft.com/en-us/defender ↗
SECURITY POSTURE

The product has a poor security track record with multiple critical and high-severity vulnerabilities, including recent zero-day privilege escalation flaws that allow attackers to bypass core security controls and escalate to SYSTEM-level access.

Notable failures
  • CVE-2026-33825: Critical local privilege escalation bypassing security controls
  • CVE-2022-44698: Critical SmartScreen bypass evading Mark of the Web protections
  • CVE-2021-1647: High remote code execution actively exploited in the wild
  • CVE-2026-41091: High local privilege escalation via link following
  • CVE-2026-45498: High denial of service impacting DIB systems
  • CVE-2026-69414: Critical zero-day privilege escalation allowing SYSTEM access
Patterns: repeated unpatched edge-device RCEs; insufficient access control granularity enabling privilege escalation; bypass vulnerabilities in core security components like SmartScreen and Malware Protection Engine
FAILURE HISTORY · 5
DATEEVENTSEVSUMMARY
2026-04-22 CVE-2026-33825 critical Microsoft Defender allows local privilege escalation via insufficient access control granularity, enabling ransomware-linked attackers to bypass security controls.
2022-12-13 CVE-2022-44698 critical A bypass vulnerability in Microsoft Defender SmartScreen allowed attackers to evade Mark of the Web protections via a crafted malicious file.
2021-11-03 CVE-2021-1647 high Microsoft Defender contained an unpatched remote code execution vulnerability that was actively exploited in the wild.
2026-05-20 CVE-2026-41091 high Microsoft Defender allows local privilege escalation via link following, enabling unauthorized access to sensitive systems.
2026-05-20 CVE-2026-45498 high Microsoft Defender allows denial of service via unspecified vulnerability, impacting DIB systems reliant on endpoint protection.
DOSSIER SOURCES
Open questions: Exact founding date of Microsoft Defender · Specific headquarters location of Microsoft Defender development
DOSSIER · dex-RAG synthesis · grounded in our own collection + trusted sourcesbuilt 2026-08-25 03:51:36.882136+00:00