How severe is CVE-2021-28476?

CVE-2021-28476 has a CVSS 3.x base score of 9.9, rated critical severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-28476 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 38% (98th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-28476?

CVE-2021-28476 primarily affects Microsoft Windows 10. In total, 18 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-28476?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2021-28476 published?

CVE-2021-28476 was published on 2021-05-11 and last updated on 2026-06-17.

CVE-2021-28476

CVE-2021-28476 is a critical-severity vulnerability in Microsoft Windows 10 with a CVSS 3.x base score of 9.9. Its EPSS exploit-prediction score of 38% places it in the 98th percentile, indicating an elevated likelihood of exploitation.

Key facts

Severity: Critical (CVSS 3.x base score 9.9)
CVSS v2: 6.5
EPSS exploit prediction: 38% (98th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Microsoft Windows 10
Published: 2021-05-11
Last modified: 2026-06-17

Description

Windows Hyper-V Remote Code Execution Vulnerability

Frequently asked questions

What is CVE-2021-28476?: Windows Hyper-V Remote Code Execution Vulnerability
How severe is CVE-2021-28476?: CVE-2021-28476 has a CVSS 3.x base score of 9.9, rated critical severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-28476 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 38% (98th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-28476?: CVE-2021-28476 primarily affects Microsoft Windows 10. In total, 18 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-28476?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-28476 published?: CVE-2021-28476 was published on 2021-05-11 and last updated on 2026-06-17.

References

Affected products (18)

cpe:2.3:o:microsoft:windows_10:-:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_10:20h2:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_10:1607:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_10:1803:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_10:1809:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_10:1909:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_10:2004:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_7:-:sp1:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_8.1:-:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2008:-:sp2:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2008:r2:sp1:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2012:-:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2012:r2:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2016:-:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2016:20h2:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2016:1909:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2016:2004:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2019:-:*:*:*:*:*:*:*

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