Remote code execution via malicious RDP server
Published Nov 10, 2021 · Updated Aug 19, 2026
Remote code execution in Microsoft Remote Desktop Client allows remote attackers to execute code when a user connects to a malicious server. Microsoft has not published the affected parsing locus or the incorrect operation performed on server-controlled RDP data. Exploitation requires user interaction with an attacker-controlled RDP endpoint and grants code execution in the client context.
Summary
What happened
Remote code execution in Microsoft Remote Desktop Client allows remote attackers to execute code when a user connects to a malicious server. Microsoft has not published the affected parsing locus or the incorrect operation performed on server-controlled RDP data. Exploitation requires user interaction with an attacker-controlled RDP endpoint and grants code execution in the client context.
The record
- CVE
- CVE-2021-38666
- Published
- Nov 10, 2021
- Updated
- Aug 19, 2026
- Vendor
- Microsoft
- Product
- Windows 10 Version 1507
- Classifications
- T1203
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Nov 10, 2021CVE publishedPublication date reported by the CVE source.
- Aug 19, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=10.0.10240.0 <10.0.10240.19119
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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