CVE-2021-38631: Windows Remote Desktop Protocol (RDP) Information Disclosure Vulnerability

Recommended actionScheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available

What, why and how

Windows Remote Desktop Protocol (RDP) Information Disclosure Vulnerability

What

Windows Remote Desktop Protocol (RDP) Information Disclosure Vulnerability

Why

The current structured CVE record identifies a security weakness, but the root cause requires confirmation in the linked vendor material.

How

An attacker operating through local access may attempt exploitation with elevated privileges. If successful, the issue may obtain information outside the intended access boundary.

What

Windows Remote Desktop Protocol (RDP) Information Disclosure Vulnerability

Why

The current structured CVE record identifies a security weakness, but the root cause requires confirmation in the linked vendor material.

How

An attacker operating through local access may attempt exploitation with elevated privileges. If successful, the issue may obtain information outside the intended access boundary.

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation

Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.

No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material

Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.

None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path: local access → vulnerable operation → obtain information outside the intended access boundary
Attack surface: Local
Privileges required: High: elevated access is required
User interaction: None
Attack complexity: Low: no specialised conditions are recorded
Security boundary: Unchanged: impact remains within the vulnerable component's security authority
Weakness ? CWE means Common Weakness Enumeration.: CWE not yet assigned
CVSS vector ? CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C
Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.
AVLocalAttack vector: The attacker needs local access to the vulnerable system.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRHighPrivileges required: The attacker needs elevated or administrative privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CHighConfidentiality impact: A successful attack can cause a major loss.INoneIntegrity impact: No direct loss is represented by this metric.ANoneAvailability impact: No direct loss is represented by this metric.
Post-exploitation / living off the land: The issue can support a local privilege or sandbox boundary transition; normal system utilities may then be available in the gained context.

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2021-25070Official EUVD mapping

Windows Remote Desktop Protocol (RDP) Information Disclosure Vulnerability

Official EUVD record ↗

Cyber Security Agency of Singapore · English · CSA-SB-20211117Security Bulletin 17 Nov 2021

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 17 Nov 2021, published on 17 November 2021. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗

CERT-FR · French · CERTFR-2021-AVI-862Multiples vulnérabilités dans Microsoft Windows

gées dans Microsoft Windows . Elles permettent à un attaquant de provoquer une atteinte à la confidentialité des données, une exécution de code à distance, une élévation de privilèges, un contournement de la fonctionnalité de sécurité et un déni de service. Solution Se référer au bulletin de sécurité de l'éditeur pour l'obtention des correctifs (cf. section Documentation). Documentation Bulletin de sécurité Microsoft du 09 novembre 2021 https://msrc.microsoft.com/update-guide/ Référence CVE CVE-2021-26443 https://www.cve.org/CVERecord?id=CVE-2021-26443 Référence CVE CVE-2021-36957 https://www.cve.org/CVERecord?id=CVE-2021-36957 Référence CVE CVE-2021-38631 https://www.cve.org/CVERecord?id=CVE-2021-38631 Référence CVE CVE-2021-38665 https://www.cve.org/CVERecord?id=CVE-2021-38665 Référence CVE CVE-2021-38666 https://www.cve.org/CVERecord?id=CVE-2021-38666 Référence CVE CVE-2021-41356 https://www.cve.org/CVERecord?id=CVE-2021-41356 Référence CVE CVE-2021-41366 https://www.cve.org/CVERecord?id=CVE-2021-41366 Référence CVE CVE-2021-41367 https://www.cve.org/CVERecord?id=CVE-2021-41367 Référence CVE CVE-2021-41370 https://www.cve.org/CVERecord?id=CVE-2021-41370 Référence CVE CVE-2021-41371 https://www.cve.org/CVERecord?id=CVE-2021-41371 Référence CVE CVE-2021-41377 https://www.cve.org/CVERecord?id=

Official advisory ↗

JVN iPedia · Japanese · JVNDB-2021-004122複数の Microsoft Windows 製品における情報を公開される脆弱性

複数の Microsoft Windows 製品には、Windows リモートデスクトッププロトコル (RDP) に不備があるため、情報を公開される脆弱性が存在します。本脆弱性は、CVE-2021-41371 とは異なる脆弱性です。

Official advisory ↗

JVN iPedia · Japanese · JVNDB-2021-004105複数の Microsoft Windows 製品における情報を公開される脆弱性

複数の Microsoft Windows 製品には、Windows リモートデスクトッププロトコル (RDP) に不備があるため、情報を公開される脆弱性が存在します。本脆弱性は、CVE-2021-38631 とは異なる脆弱性です。

Official advisory ↗

KISA KrCERT/CC · Korean · KNVD-5435MS 11월 보안 위협에 따른 정기 보안 업데이트 권고

on of Privilege Vulnerability Windows Feedback Hub CVE-2021-42280 Windows 피드백 허브 권한 상승 취약성 Windows Hello CVE-2021-42288 Windows Hello 보안 기능 우회 취약성 Windows Installer CVE-2021-41379 Windows Installer 권한 상승 취약성 Windows Kernel CVE-2021-42285 Windows 커널 권한 상승 취약성 Windows NTFS CVE-2021-42283 NTFS 권한 상승 취약성 Windows NTFS CVE-2021-41378 Windows NTFS Remote Code Execution Vulnerability Windows NTFS CVE-2021-41370 NTFS 권한 상승 취약성 Windows NTFS CVE-2021-41367 NTFS 권한 상승 취약성 Windows RDP CVE-2021-41371 Windows RDP(원격 데스크톱 프로토콜) 정보 유출 취약성 Windows RDP CVE-2021-38666 원격 데스크톱 클라이언트 원격 코드 실행 취약성 Windows RDP CVE-2021-38665 원격 데스크톱 프로토콜 클라이언트 정보 유출 취약성 Windows RDP CVE-2021-38631 Windows RDP(원격 데스크톱 프로토콜) 정보 유출 취약성 Windows Scripting CVE-2021-42279 Chakra 스크립팅 엔진 메모리 손상 취약성 Windows Virtual Machine Bus CVE-2021-26443 Microsoft Virtual Machine Bus (VMBus) Remote Code Execution Vulnerability ##### □ 작성 : 침해사고분석단 취약점분석팀

Official advisory ↗

Patch and workaround

Operational remediation based on structured source evidence.

Status ? Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.: Patch available
Affected: Windows 10 Version 1507: 10.0.10240.0 < 10.0.10240.19119
Windows 10 Version 1607: 10.0.14393.0 < 10.0.14393.4770
Windows 10 Version 1809: 10.0.17763.0 < 10.0.17763.2300, 10.0.0 < 10.0.17763.2300
Windows 10 Version 1909: 10.0.0 < 10.0.18363.1916
Windows 10 Version 2004: 10.0.0 < 10.0.19041.1348
Windows 10 Version 20H2: 10.0.0 < 10.0.19042.1348
Windows 10 Version 21H1: 10.0.0 < 10.0.19043.1348
Windows 11 version 21H2: 10.0.22000.0 < 10.0.22000.318
Windows 7: 6.1.0 < 6.1.7601.25769
Windows 7 Service Pack 1: 6.1.0 < 6.1.7601.25769
Windows 8.1: 6.3.0 < 6.3.9600.20174
Windows Server 2008 R2 Service Pack 1: 6.1.7601.0 < 6.1.7601.25769
Windows Server 2008 R2 Service Pack 1 (Server Core installation): 6.1.7601.0 < 6.1.7601.25769
Windows Server 2008 Service Pack 2: 6.0.6003.0 < 6.0.6003.21282
Windows Server 2008 Service Pack 2 (Server Core installation): 6.0.6003.0 < 6.0.6003.21282
Windows Server 2012: 6.2.9200.0 < 6.2.9200.23517
Windows Server 2012 (Server Core installation): 6.2.9200.0 < 6.2.9200.23517
Windows Server 2012 R2: 6.3.9600.0 < 6.3.9600.20174
Windows Server 2012 R2 (Server Core installation): 6.3.9600.0 < 6.3.9600.20174
Windows Server 2016: 10.0.14393.0 < 10.0.14393.4770
Windows Server 2016 (Server Core installation): 10.0.14393.0 < 10.0.14393.4770
Windows Server 2019: 10.0.17763.0 < 10.0.17763.2300
Windows Server 2019 (Server Core installation): 10.0.17763.0 < 10.0.17763.2300
Windows Server 2022: 10.0.20348.0 < 10.0.20348.350
Windows Server version 2004: 10.0.0 < 10.0.19041.1348
Windows Server version 20H2: 10.0.0 < 10.0.19041.1348
Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
Action: Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround: No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.

Evidence and provenance

Published 10 Nov 2021 · Last source change 19 Aug 2026, 16:27 UTC · CWE not yet assigned

CVE recordCVE.org · 5.2

CVSS sourceCNA

EPSS source

The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.

FIRST · tracked since 2026-08-14

European sourceENISA EUVD · EUVD-2021-25070

Product sourceCNA

Remediation sourceCVE/CNA references

CWE sourceUnavailable

NVD statusNVD modified after enrichment

Missing structured fields: CWE classification. Missing data is not evidence of low risk; review the primary advisory.

Material change intelligence

What changed after publication

View recent updates ↗

19 Aug 2026, 16:27 UTC
Vendor guidanceAuthoritative vendor guidance changed: added remediation: portal.msrc.microsoft.com/CVE-2021-38631; removed patch: msrc.microsoft.com/CVE-2021-38631; removed remediation: msrc.microsoft.com/CVE-2021-38631.
Before
patch: msrc.microsoft.com/CVE-2021-38631 · patch: portal.msrc.microsoft.com/CVE-2021-38631 · remediation: msrc.microsoft.com/CVE-2021-38631
After
patch: portal.msrc.microsoft.com/CVE-2021-38631 · remediation: portal.msrc.microsoft.com/CVE-2021-38631
portal.msrc.microsoft.com ↗
19 Aug 2026, 16:27 UTC
Vendor guidanceAuthoritative vendor guidance changed: added patch: msrc.microsoft.com/CVE-2021-38631; added remediation: msrc.microsoft.com/CVE-2021-38631; removed remediation: portal.msrc.microsoft.com/CVE-2021-38631.
Before
patch: portal.msrc.microsoft.com/CVE-2021-38631 · remediation: portal.msrc.microsoft.com/CVE-2021-38631
After
patch: msrc.microsoft.com/CVE-2021-38631 · patch: portal.msrc.microsoft.com/CVE-2021-38631 · remediation: msrc.microsoft.com/CVE-2021-38631
msrc.microsoft.com ↗
19 Aug 2026, 16:27 UTC
Affected versionsThe structured affected or fixed version information changed.
Before
10.0.0 < 10.0.17763.2300; 10.0.0 < 10.0.18363.1916; 10.0.0 < 10.0.19043.1348; 10.0.0 < 10.0.20348.350; 10.0.0 < 10.0.19041.1348 · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
After
10.0.10240.0 < 10.0.10240.19119; 10.0.14393.0 < 10.0.14393.4770; 10.0.17763.0 < 10.0.17763.2300; 10.0.0 < 10.0.17763.2300; 10.0.0 < 10.0.18363.1916; 10.0.0 < 10.0.19041.1348; 10.0.0 < 10.0.19042.1348; 10.0.0 < 10.0.19043.1348 · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
CNA ↗

2021-11-10CVE published

2026-08-19Fixed release or patch reference recorded

ENISA EUVD · EUVD-2021-25070↗Patch or update reference↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗

Technical terms and abbreviations used in this report

CVE: Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS: Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS: Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE: Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA: CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP: Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD: National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT: A computer security incident response team that publishes warnings or coordinates incident response.
PoC: Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF: Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL: Living off the land: abuse of legitimate tools or system functions during an attack.

Windows Remote Desktop Protocol (RDP) Information Disclosure Vulnerability

Published severity in operational context

Evidence used

Compensating controls

Verification

National CERT insights
?
CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

ENISA European Vulnerability Database

EUVD-2021-25070

What, why and how

Exploit reality and attack path

Official authority intelligence

Patch and workaround

Evidence and provenance

What changed after publication