What’s Vulnerable › Vulnerabilities

CVE-2021-34471: Microsoft Defender Elevation of Privilege Vulnerability

• Severity: medium (CVSS 4.6 v2.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-08-12 · updated 2026-08-10
• Weakness: CWE-269

Description

Microsoft Defender Elevation of Privilege Vulnerability

Affected products

• Microsoft Malware Protection Engine: before 1.1.18400.4 — fixed in 1.1.18400.4
• Microsoft Malware Protection Engine: from 1.1.0.0 before 1.1.18400.4 — fixed in 1.1.18400.4

How to fix

Upgrade to a fixed version: Microsoft Malware Protection Engine 1.1.18400.4; Microsoft Malware Protection Engine 1.1.18400.4. Check the vendor advisory for mitigations.

References

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-34471
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-34471

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