Heap-address disclosure via printer cache name
Published Nov 10, 2021 · Updated Aug 19, 2026
Information disclosure in Microsoft Remote Desktop clients allows remote attackers to read heap data after a user connects to a malicious RDP server. The RDPDR printer subprotocol's W32DrPRN::AddPrinterCacheInfo path passes an attacker-controlled PrinterName lacking a length check and double-null termination to RegCreateKeyExW, causing an out-of-bounds heap read during printer-cache key creation. Exploitation requires user interaction to initiate the connection; the disclosed heap addresses can weaken ASLR but do not directly alter data or interrupt service.
Summary
What happened
Information disclosure in Microsoft Remote Desktop clients allows remote attackers to read heap data after a user connects to a malicious RDP server. The RDPDR printer subprotocol's W32DrPRN::AddPrinterCacheInfo path passes an attacker-controlled PrinterName lacking a length check and double-null termination to RegCreateKeyExW, causing an out-of-bounds heap read during printer-cache key creation. Exploitation requires user interaction to initiate the connection; the disclosed heap addresses can weaken ASLR but do not directly alter data or interrupt service.
The record
- CVE
- CVE-2021-38665
- Published
- Nov 10, 2021
- Updated
- Aug 19, 2026
- Vendor
- Microsoft
- Product
- Windows 10 Version 1507
- Classifications
- Unavailable
- 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?
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
No sourced classifications are available.
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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