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CVE-2021-34487: Windows Event Tracing Elevation of Privilege Vulnerability

• Severity: medium (CVSS 4.6 v2.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% 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

Windows Event Tracing Elevation of Privilege Vulnerability

Affected products

• Microsoft Windows 10 Version 1607: 20h2, 21h1, 1607, 1809, 1909, 2004
• Microsoft Windows Server 2016: 20h2, 2004
• Microsoft Windows Server 2019: all versions
• Microsoft Windows 10 1607: from 10.0.14393.0 before 10.0.14393.4583 — fixed in 10.0.14393.4583
• Microsoft Windows 10: from 10.0.17763.0 before 10.0.17763.2114 — fixed in 10.0.17763.2114
• Microsoft Windows 10 1909: from 10.0.0 before 10.0.18363.1734 — fixed in 10.0.18363.1734
• Microsoft Windows 10 2004: from 10.0.0 before 10.0.19041.1165 — fixed in 10.0.19041.1165
• Microsoft Windows 10 20H2: from 10.0.0 before 10.0.19042.1165 — fixed in 10.0.19042.1165
• Microsoft Windows 10 21H1: from 10.0.0 before 10.0.19043.1165 — fixed in 10.0.19043.1165
• Microsoft Windows Server 2016: from 10.0.14393.0 before 10.0.14393.4583 — fixed in 10.0.14393.4583
• Microsoft Windows Server 2019: from 10.0.17763.0 before 10.0.17763.2114 — fixed in 10.0.17763.2114
• Microsoft Windows Server version 2004: from 10.0.0 before 10.0.19041.1165 — fixed in 10.0.19041.1165
• Microsoft Windows Server version 20H2: from 10.0.0 before 10.0.19042.1165 — fixed in 10.0.19042.1165

How to fix

Upgrade to a fixed version: Microsoft Windows 10 1607 10.0.14393.4583; Microsoft Windows 10 10.0.17763.2114; Microsoft Windows 10 1909 10.0.18363.1734; Microsoft Windows 10 2004 10.0.19041.1165; Microsoft Windows 10 20H2 10.0.19042.1165; Microsoft Windows 10 21H1 10.0.19043.1165; Microsoft Windows Server 2016 10.0.14393.4583; Microsoft Windows Server 2019 10.0.17763.2114; Microsoft Windows Server version 2004 10.0.19041.1165; Microsoft Windows Server version 20H2 10.0.19042.1165. Check the vendor advisory for mitigations.

References

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-34487
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-34487

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