CVE-2021-1669 — Windows Remote Desktop Security Feature Bypass Vulnerability

Executive Summary

None

Overview

8.8

CVSS HIGH

Important

MS Severity

Not Exploited

MS Exploit Status

Less Likely

MS Exploit Likelihood

Category Security Feature Bypass

Released Jan 12 2021

Last Updated Jan 12 2021

Publicly Disclosed No

CISA KEV Not Listed

Known Exploits None Known

EPSS Score 0.02967 — 0.85459 percentile

CVSS Vector

ATTACK VECTOR

Network

ATTACK COMPLEXITY

Low

PRIVILEGES REQUIRED

Low

USER INTERACTION

None

SCOPE

Unchanged

Temporal Score: 7.7

EPSS Score

0.02967

probability of exploitation in the next 30 days

0.85459 percentile - updated 2026-06-20

View on FIRST.org

Affected Products

28 affected products

Product	KB Article	Severity	Impact	Restart Required
Microsoft Remote Desktop for IoS	`Release Notes (Security Update) Release Notes (Security Update) Release Notes (Security Update)`	Important	Security Feature Bypass	Maybe
Microsoft Remote Desktop for Mac	`Release Notes (Security Update) Release Notes (Security Update) Release Notes (Security Update)`	Important	Security Feature Bypass	Maybe
Remote Desktop client for Windows Desktop	`Release Notes (Security Update) Release Notes (Security Update) Release Notes (Security Update)`	Important	Security Feature Bypass	Maybe
Windows 10 for 32-bit Systems	`4598231 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 for x64-based Systems	`4598231 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 1607 for 32-bit Systems	`4598243 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 1607 for x64-based Systems	`4598243 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 1803 for 32-bit Systems	`4598245 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 1803 for ARM64-based Systems	`4598245 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 1803 for x64-based Systems	`4598245 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 1809 for 32-bit Systems	`4598230 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 1809 for ARM64-based Systems	`4598230 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 1809 for x64-based Systems	`4598230 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 1909 for 32-bit Systems	`4598229 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 1909 for ARM64-based Systems	`4598229 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 1909 for x64-based Systems	`4598229 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 2004 for 32-bit Systems	`4598242 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 2004 for ARM64-based Systems	`4598242 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 2004 for x64-based Systems	`4598242 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 20H2 for 32-bit Systems	`4598242 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 20H2 for ARM64-based Systems	`4598242 (Security Update)`	Important	Security Feature Bypass	Yes
Windows 10 Version 20H2 for x64-based Systems	`4598242 (Security Update)`	Important	Security Feature Bypass	Yes
Windows Server 2016	`4598243 (Security Update)`	Important	Security Feature Bypass	Yes
Windows Server 2016 (Server Core installation)	`4598243 (Security Update)`	Important	Security Feature Bypass	Yes
Windows Server 2019	`4598230 (Security Update)`	Important	Security Feature Bypass	Yes
Windows Server, version 1909 (Server Core installation)	`4598229 (Security Update)`	Important	Security Feature Bypass	Yes
Windows Server, version 2004 (Server Core installation)	`4598242 (Security Update)`	Important	Security Feature Bypass	Yes
Windows Server, version 20H2 (Server Core Installation)	`4598242 (Security Update)`	Important	Security Feature Bypass	Yes

Patches

7 patches

Article	Type	Restart
`Release Notes (Security Update) Release Notes (Security Update) Release Notes`	Security Update	Maybe
`4598231`	Security Update	Yes
`4598243`	Security Update	Yes
`4598245`	Security Update	Yes
`4598230`	Security Update	Yes
`4598229`	Security Update	Yes
`4598242`	Security Update	Yes

Known Exploits

No known exploits have been linked for this CVE yet. When available, exploit references will be sourced from public repositories and may be unverified, incomplete, or non-functional. Always review code carefully before use in any environment.

Acknowledgments

Microsoft has not published researcher acknowledgments for this CVE, or they are not yet reflected in our data source. Check the MSRC advisory directly for the most current credit information.

References

MSRC Advisory MITRE NVD