# Windows Hyper-V Elevation of Privilege Vulnerability

CVE record · `CVE-2021-28314`

- **Identifiers:** `CVE-2021-28314`
- **State:** Confirmed
- **Severity:** CVSS 7.8 High
- **Critical:** No
- **CNA:** microsoft
- **Technologies:** [Microsoft Windows 10 Version 1809](https://agentprime.io/advisories/technology/microsoft-windows-10-version-1809.md) · [Microsoft Windows Server 2019](https://agentprime.io/advisories/technology/microsoft-windows-server-2019.md) · [Microsoft Windows Server 2019 (Server Core installation)](https://agentprime.io/advisories/technology/microsoft-windows-server-2019-server-core-installation.md) · [Microsoft Windows 10 Version 1909](https://agentprime.io/advisories/technology/microsoft-windows-10-version-1909.md) · [Microsoft Windows Server, version 1909 (Server Core installation)](https://agentprime.io/advisories/technology/microsoft-windows-server-version-1909-server-core-installation.md) · [Microsoft Windows 10 Version 2004](https://agentprime.io/advisories/technology/microsoft-windows-10-version-2004.md) · [Microsoft Windows Server version 2004](https://agentprime.io/advisories/technology/microsoft-windows-server-version-2004.md) · [Microsoft Windows 10 Version 20H2](https://agentprime.io/advisories/technology/microsoft-windows-10-version-20h2.md) · [Microsoft Windows Server version 20H2](https://agentprime.io/advisories/technology/microsoft-windows-server-version-20h2.md)
- **Published:** 13 Apr 2021
- **Updated:** 3 Aug 2024
- **Reviewed by a person:** No

Published by the CVE Program (CNA: microsoft) at 13 Apr 2021, 19:32 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it.

## Affected products, as the CNA wrote them

- Vendor: Microsoft. Product: Windows 10 Version 1809.
  - affected: `10.0.0 to before publication` (custom)
- Vendor: Microsoft. Product: Windows Server 2019.
  - affected: `10.0.0 to before publication` (custom)
- Vendor: Microsoft. Product: Windows Server 2019 (Server Core installation).
  - affected: `10.0.0 to before publication` (custom)
- Vendor: Microsoft. Product: Windows 10 Version 1909.
  - affected: `10.0.0 to before publication` (custom)
- Vendor: Microsoft. Product: Windows Server, version 1909 (Server Core installation).
  - affected: `10.0.0 to before publication` (custom)
- Vendor: Microsoft. Product: Windows 10 Version 2004.
  - affected: `10.0.0 to before publication` (custom)
- Vendor: Microsoft. Product: Windows Server version 2004.
  - affected: `10.0.0 to before publication` (custom)
- Vendor: Microsoft. Product: Windows 10 Version 20H2.
  - affected: `10.0.0 to before publication` (custom)
- Vendor: Microsoft. Product: Windows Server version 20H2.
  - affected: `10.0.0 to before publication` (custom)

## Not analysed yet

We haven’t published our own analysis of this CVE. If a person reviews it, this page will say what’s affected and what has to be true for it to matter.

## Severity and exploitation

- 7.8 High, CVSS 3.1: `CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C`, from CNA (microsoft)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0063, the 50th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

This record came from the full history of the CVE Program, published 13 Apr 2021. New records show when each source confirmed them.

## Sources

- [CVE List: CVE-2021-28314](https://www.cve.org/CVERecord?id=CVE-2021-28314)
- [NVD: CVE-2021-28314](https://nvd.nist.gov/vuln/detail/CVE-2021-28314)

### References from the CNA

- <https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-28314>

Facts on this page come from the CVE List as the CNA published them, with CVSS from the sources named above, CISA KEV and FIRST EPSS. Vendors, products and versions are shown as the CNA wrote them. We don’t reproduce the CVE’s description.

## Check whether this affects you

This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it. Compare the affected versions above with what you run.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), `get_advisory` returns this record and `search_advisories` finds related ones. Setup: <https://agentprime.io/mcp.md>
- As JSON: <https://api.agentprime.io/v1/advisories/CVE-2021-28314>
- Everything that needs attention now: <https://agentprime.io/advisories/critical.md>

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The web page: <https://agentprime.io/advisories/CVE-2021-28314/>. Everything for agents: <https://agentprime.io/llms.txt>.