OnlyFm252
Windows RDP

CVE-2021-38666 — Remote Desktop Client Remote Code Execution Vulnerability

Critical CVSS 8.8 EPSS 0.12993 2021-11 archive

Executive Summary

None

Overview

8.8
CVSS HIGH
Critical
MS Severity
Not Exploited
MS Exploit Status
More Likely
MS Exploit Likelihood
Category Remote Code Execution
Released Nov 9 2021
Last Updated Nov 9 2021
Publicly Disclosed No
CISA KEV Not Listed
Known Exploits None Known
EPSS Score 0.12993 — 0.95827 percentile
NVD CVSS 8.8 HIGH — matches MSRC

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
ATTACK VECTOR
Network
ATTACK COMPLEXITY
Low
PRIVILEGES REQUIRED
None
USER INTERACTION
Required
SCOPE
Unchanged
CONFIDENTIALITY
High
INTEGRITY
High
AVAILABILITY
High
EXPLOIT CODE MATURITY
Unproven
REMEDIATION LEVEL
Official Fix
REPORT CONFIDENCE
Confirmed
Temporal Score: 7.7

EPSS Score

0.12993
probability of exploitation in the next 30 days
0.95827 percentile - updated 2026-06-21
View on FIRST.org

Affected Products

29 affected products
Product KB Article Severity Impact Restart Required
Remote Desktop client for Windows Desktop Critical Remote Code Execution None Base: 8.8 Temporal: 7.7 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C Unknown Unknown None Windows 10 for 32-bit Systems 5007207 (Security Update) Critical Remote Code Execution Yes
Windows 10 for x64-based Systems 5007207 (Security Update) Critical Remote Code Execution Yes
Windows 10 Version 1607 for 32-bit Systems 5007192 (Security Update) Critical Remote Code Execution Yes
Windows 10 Version 1607 for x64-based Systems 5007192 (Security Update) Critical Remote Code Execution Yes
Windows 10 Version 1809 for 32-bit Systems 5007206 (Security Update) Critical Remote Code Execution Yes
Windows 10 Version 1809 for ARM64-based Systems 5007206 (Security Update) Critical Remote Code Execution Yes
Windows 10 Version 1809 for x64-based Systems 5007206 (Security Update) Critical Remote Code Execution Yes
Windows 10 Version 1909 for 32-bit Systems 5007189 (Security Update) Critical Remote Code Execution Yes
Windows 10 Version 1909 for ARM64-based Systems 5007189 (Security Update) Critical Remote Code Execution Yes
Windows 10 Version 1909 for x64-based Systems 5007189 (Security Update) Critical Remote Code Execution Yes
Windows 10 Version 2004 for 32-bit Systems 5007186 (Security Update) Critical Remote Code Execution Yes
Windows 10 Version 2004 for ARM64-based Systems 5007186 (Security Update) Critical Remote Code Execution Yes
Windows 10 Version 2004 for x64-based Systems 5007186 (Security Update) Critical Remote Code Execution Yes
Windows 10 Version 20H2 for 32-bit Systems 5007186 (Security Update) Critical Remote Code Execution Yes
Windows 10 Version 20H2 for ARM64-based Systems 5007186 (Security Update) Critical Remote Code Execution Yes
Windows 10 Version 21H1 for 32-bit Systems 5007186 (Security Update) Critical Remote Code Execution Yes
Windows 10 Version 21H1 for ARM64-based Systems 5007186 (Security Update) Critical Remote Code Execution Yes
Windows 10 Version 21H1 for x64-based Systems 5007186 (Security Update) Critical Remote Code Execution Yes
Windows 11 version 21H2 for ARM64-based Systems 5007215 (Security Update) Critical Remote Code Execution Yes
Windows 11 version 21H2 for x64-based Systems 5007215 (Security Update) Critical Remote Code Execution Yes
Windows 7 for 32-bit Systems Service Pack 1 5007236 (Monthly Rollup) 5007233 (Security Only) Critical Remote Code Execution 5006743 Base: 8.8 Temporal: 7.7 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 6.1.7601.25769 Yes 5007236 5007233 Windows 7 for x64-based Systems Service Pack 1 5007236 (Monthly Rollup) 5007233 (Security Only) Critical Remote Code Execution 5006743 Base: 8.8 Temporal: 7.7 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 6.1.7601.25769 Yes 5007236 5007233 Windows 8.1 for 32-bit systems 5007247 (Monthly Rollup) 5007255 (Security Only) Critical Remote Code Execution 5006714 Base: 8.8 Temporal: 7.7 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 6.3.9600.20174 Yes 5007247 5007255 Windows 8.1 for x64-based systems 5007247 (Monthly Rollup) 5007255 (Security Only) Critical Remote Code Execution 5006714 Base: 8.8 Temporal: 7.7 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 6.3.9600.20174 Yes 5007247 5007255 Windows RT 8.1 5007247 (Monthly Rollup) Critical Remote Code Execution Yes
Windows Server 2008 for 32-bit Systems Service Pack 2 5007263 (Monthly Rollup) 5007246 (Security Only) Critical Remote Code Execution 5006736 Base: 8.8 Temporal: 7.7 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 6.0.6003.21282 Yes 5007263 5007246 Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation) 5007263 (Monthly Rollup) 5007246 (Security Only) Critical Remote Code Execution 5006736 Base: 8.8 Temporal: 7.7 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 6.0.6003.21282 Yes 5007263 5007246 Windows Server 2008 for x64-based Systems Service Pack 2 5007263 (Monthly Rollup) 5007246 (Security Only) Critical Remote Code Execution 5006736 Base: 8.8 Temporal: 7.7 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 6.0.6003.21282 Yes 5007263 5007246 Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation) 5007263 (Monthly Rollup) 5007246 (Security Only) Critical Remote Code Execution 5006736 Base: 8.8 Temporal: 7.7 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 6.0.6003.21282 Yes 5007263 5007246 Windows Server 2008 R2 for x64-based Systems Service Pack 1 5007236 (Monthly Rollup) 5007233 (Security Only) Critical Remote Code Execution 5006743 Base: 8.8 Temporal: 7.7 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 6.1.7601.25769 Yes 5007236 5007233 Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation) 5007236 (Monthly Rollup) 5007233 (Security Only) Critical Remote Code Execution 5006743 Base: 8.8 Temporal: 7.7 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 6.1.7601.25769 Yes 5007236 5007233 Windows Server 2012 5007260 (Monthly Rollup) 5007245 (Security Only) Critical Remote Code Execution 5006739 Base: 8.8 Temporal: 7.7 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 6.2.9200.23517 Yes 5007260 5007245 Windows Server 2012 (Server Core installation) 5007260 (Monthly Rollup) 5007245 (Security Only) Critical Remote Code Execution 5006739 Base: 8.8 Temporal: 7.7 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 6.2.9200.23517 Yes 5007260 5007245 Windows Server 2012 R2 5007247 (Monthly Rollup) 5007255 (Security Only) Critical Remote Code Execution 5006714 Base: 8.8 Temporal: 7.7 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 6.3.9600.20174 Yes 5007247 5007255 Windows Server 2012 R2 (Server Core installation) 5007247 (Monthly Rollup) 5007255 (Security Only) Critical Remote Code Execution 5006714 Base: 8.8 Temporal: 7.7 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 6.3.9600.20174 Yes 5007247 5007255 Windows Server 2016 5007192 (Security Update) Critical Remote Code Execution Yes
Windows Server 2016 (Server Core installation) 5007192 (Security Update) Critical Remote Code Execution Yes
Windows Server 2019 5007206 (Security Update) Critical Remote Code Execution Yes
Windows Server 2019 (Server Core installation) 5007206 (Security Update) Critical Remote Code Execution Yes
Windows Server 2022 5007205 (Security Update) Critical Remote Code Execution Yes
Windows Server 2022 (Server Core installation) 5007205 (Security Update) Critical Remote Code Execution Yes
Windows Server, version 2004 (Server Core installation) 5007186 (Security Update) Critical Remote Code Execution Yes
Windows Server, version 20H2 (Server Core Installation) 5007186 (Security Update) Critical Remote Code Execution Yes

Patches

8 patches
Article Type Restart
5007207 Security Update Yes
5007192 Security Update Yes
5007206 Security Update Yes
5007189 Security Update Yes
5007186 Security Update Yes
5007215 Security Update Yes
5007247 Monthly Rollup Yes
5007205 Security Update Yes

Known Exploits

Acknowledgments

Valentino Ricotta with Thalium

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