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CVE-2021-42274: Windows Hyper-V Discrete Device Assignment (DDA) Denial of Service Vulnerability

• Severity: low (CVSS 2.1 v2.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.7% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-11-10 · updated 2026-08-19

Description

Windows Hyper-V Discrete Device Assignment (DDA) Denial of Service Vulnerability

Affected products

• Microsoft Windows 10 Version 1607: 20h2, 21h1, 1607, 1809, 2004
• Microsoft Windows 11 version 21H2: all versions
• Microsoft Windows Server 2016: 20h2, 2004
• Microsoft Windows Server 2019: all versions
• Microsoft Windows Server 2022: all versions
• Microsoft Windows 10 1607: from 10.0.14393.0 before 10.0.14393.4770 — fixed in 10.0.14393.4770
• Microsoft Windows 10: from 10.0.17763.0 before 10.0.17763.2300 — fixed in 10.0.17763.2300
• Microsoft Windows 10 2004: from 10.0.0 before 10.0.19041.1348 — fixed in 10.0.19041.1348
• Microsoft Windows 10 21H1: from 10.0.0 before 10.0.19043.1348 — fixed in 10.0.19043.1348
• Microsoft Windows 11 21H2: from 10.0.22000.0 before 10.0.22000.318 — fixed in 10.0.22000.318
• Microsoft Windows Server 2016: from 10.0.14393.0 before 10.0.14393.4770 — fixed in 10.0.14393.4770
• Microsoft Windows Server 2019: from 10.0.17763.0 before 10.0.17763.2300 — fixed in 10.0.17763.2300
• Microsoft Windows Server 2022: from 10.0.20348.0 before 10.0.20348.350 — fixed in 10.0.20348.350
• Microsoft Windows Server version 2004: from 10.0.0 before 10.0.19041.1348 — fixed in 10.0.19041.1348
• Microsoft Windows Server version 20H2: from 10.0.0 before 10.0.19041.1348 — fixed in 10.0.19041.1348

How to fix

Upgrade to a fixed version: Microsoft Windows 10 1607 10.0.14393.4770; Microsoft Windows 10 10.0.17763.2300; Microsoft Windows 10 2004 10.0.19041.1348; Microsoft Windows 10 21H1 10.0.19043.1348; Microsoft Windows 11 21H2 10.0.22000.318; Microsoft Windows Server 2016 10.0.14393.4770; Microsoft Windows Server 2019 10.0.17763.2300; Microsoft Windows Server 2022 10.0.20348.350; Microsoft Windows Server version 2004 10.0.19041.1348; Microsoft Windows Server version 20H2 10.0.19041.1348. Check the vendor advisory for mitigations.

References

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-42274
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-42274

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