What’s Vulnerable › Vulnerabilities

CVE-2021-34522: Microsoft Defender Remote Code Execution Vulnerability

• Severity: critical (CVSS 9.3 v2.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 2.7% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-07-14 · updated 2026-08-10

Description

Microsoft Defender Remote Code Execution Vulnerability

Affected products

• Microsoft Malware Protection Engine: before 1.1.18242.0 — fixed in 1.1.18242.0
• Microsoft Malware Protection Engine: from 1.1.0.0 before 1.1.18242.0 — fixed in 1.1.18242.0

How to fix

Upgrade to a fixed version: Microsoft Malware Protection Engine 1.1.18242.0; Microsoft Malware Protection Engine 1.1.18242.0. Check the vendor advisory for mitigations.

References

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-34522
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-34522

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