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Full vulnerability report · 2023
CVE-2023-21820High confidence

Windows Distributed File System (DFS) Remote Code Execution Vulnerability

Microsoft · Windows 10 Version 1507

7.4HighCVSS 3.1
Recommended action
Within 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Patch available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityHighOperational priority:High, unchanged from published severity.unchanged

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • EPSS is 0.63% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • Restrict local access and enforce least privilege on affected hosts.
  • Monitor vendor guidance and exploitation sources for a material change.

Verification

  1. Confirm that the asset runs Microsoft Windows 10 Version 1507 and falls inside the recorded affected range.
  2. Verify the installed build against the product-specific fixed version after deployment.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: Within 30 daysRemediation target: Within 180 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Optional official sources

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

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2023-25986

No EUVD known-exploited evidence

Windows Distributed File System (DFS) Remote Code Execution Vulnerability

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
7.4 · CVSS 3.1
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Patch available
01

What, why and how

Windows Distributed File System (DFS) Remote Code Execution Vulnerability

What

Windows Distributed File System (DFS) Remote Code Execution Vulnerability

Why

The product reads from a buffer using buffer access mechanisms such as indexes or pointers that reference memory locations after the targeted buffer.

How

An attacker operating through an adjacent network may attempt exploitation with low privileges. If successful, the issue may execute code or commands in the affected security context.

What

Windows Distributed File System (DFS) Remote Code Execution Vulnerability

Why

The product reads from a buffer using buffer access mechanisms such as indexes or pointers that reference memory locations after the targeted buffer.

How

An attacker operating through an adjacent network may attempt exploitation with low privileges. If successful, the issue may execute code or commands in the affected security context.

02

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
an adjacent network → Buffer Over-read → execute code or commands in the affected security context
Attack surface
Adjacent
Privileges required
Low: a basic authenticated account is required
User interaction
Required interaction required
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: a standard category for the underlying weakness.
CWE-126 ↗

CWE-126: Buffer Over-read. The product reads from a buffer using buffer access mechanisms such as indexes or pointers that reference memory locations after the targeted buffer.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:A/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVAdjacentAttack vector: The attacker must be on an adjacent or logically close network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRLowPrivileges required: The attacker needs basic user-level privileges.UIRequiredUser interaction: Another user must perform an action for exploitation to succeed.SUnchangedScope: The security impact remains within the vulnerable component's authority.CHighConfidentiality impact: A successful attack can cause a major loss.IHighIntegrity impact: A successful attack can cause a major loss.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land
After compromise, an attacker may use built-in shells, scripting engines, scheduled tasks and native network utilities for discovery, persistence or movement. This is a plausible LoTL path, not evidence that it has occurred for every attack.
Remote code executionCWE-126
A

Official authority intelligence

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

ENISA EUVD · EUVD-2023-25986Official EUVD mapping

Windows Distributed File System (DFS) Remote Code Execution Vulnerability

Official EUVD record ↗
Cyber Security Agency of Singapore · English · CSA-SB-20230215Security Bulletin 15 Feb 2023

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 15 Feb 2023, published on 15 February 2023. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2023-AVI-0130Multiples vulnérabilités dans Microsoft Windows

février 2023 https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21813 Bulletin de sécurité Microsoft CVE-2023-21816 du 14 février 2023 https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21816 Bulletin de sécurité Microsoft CVE-2023-21817 du 14 février 2023 https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21817 Bulletin de sécurité Microsoft CVE-2023-21818 du 14 février 2023 https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21818 Bulletin de sécurité Microsoft CVE-2023-21819 du 14 février 2023 https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21819 Bulletin de sécurité Microsoft CVE-2023-21820 du 14 février 2023 https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21820 Bulletin de sécurité Microsoft CVE-2023-21822 du 14 février 2023 https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21822 Bulletin de sécurité Microsoft CVE-2023-21823 du 14 février 2023 https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21823 Bulletin de sécurité Microsoft CVE-2023-23376 du 14 février 2023 https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-23376 Référence CVE CVE-2023-21684 https://www.cve.org/CVERecord?id=CVE-2023-21684 Référence CVE CVE-2023-21685 https://www.cve.org/CVERecord?id=CVE-2023-21685 Référ

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2023-001293複数の Microsoft Windows 製品におけるリモートでコードを実行される脆弱性

Microsoft Windows 10、Windows 11、Windows Server には、Windows 分散ファイル システム (DFS) に不備があるため、リモートでコードを実行される脆弱性が存在します。

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-5870MS 2월 보안 위협에 따른 정기 보안 업데이트 권고

UI Clone 원격 코드 실행 취약점 3D Builder CVE-2023-23390 3D Builder 원격 코드 실행 취약점 Azure Machine Learning CVE-2023-23382 Azure 기계 학습 컴퓨팅 인스턴스 정보 공개 취약점 Visual Studio CVE-2023-23381 Visual Studio 원격 코드 실행 취약점 Microsoft Defender for IoT CVE-2023-23379 IoT용 Microsoft Defender에서 발생하는 권한 상승 취약점 3D Builder CVE-2023-23378 Print 3D 원격 코드 실행 취약점 3D Builder CVE-2023-23377 3D Builder 원격 코드 실행 취약점 Windows Common Log File System Driver CVE-2023-23376 Windows Common Log File System Driver 권한 상승 취약점 Microsoft Graphics Component CVE-2023-21823 Windows 그래픽 구성 요소 원격 코드 실행 취약점 Windows Win32K CVE-2023-21822 Windows 그래픽 구성 요소 권한 상승 취약점 Windows Distributed File System (DFS) CVE-2023-21820 Windows 분산 파일 시스템(DFS) 원격 코드 실행 취약점 Windows Cryptographic Services CVE-2023-21819 Windows 보안 채널 서비스 거부 취약점 Windows SChannel CVE-2023-21818 Windows 보안 채널 서비스 거부 취약점 Windows Kerberos CVE-2023-21817 Windows Kerberos 권한 상승 취약점 Windows Active Directory CVE-2023-21816 Windows Active Directory 도메인 서비스 API 서비스 거부 취약점 Visual Studio CVE-2023-21815 Visual Studio 원격 코드 실행 취약점 Windows Cryptographic Services CVE-2023-21813 Windows 보안 채널 서비스 거부 취약점 Windows Common Log File System Driver CVE-2023-21812 Windows Common Log File System Driver 권한 상승 취약점 Windows iSCSI CVE-2023-21811 Windows iSCSI Service에서 발생하는 서비스 거부 취약점 Microsoft Defender for Endpoint CVE-2023-

Official advisory ↗
03

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
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.
04

Evidence and provenance

Published 14 Feb 2023 · Last source change 19 Aug 2026, 16:26 UTC · CWE-126 · Buffer Over-read

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-2023-25986
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceOther authority
NVD statusNVD modified after enrichment

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗
  1. Affected versionsThe structured affected or fixed version information changed.
    Before
    10.0.17763.0 < 10.0.17763.4010; 10.0.0 < 10.0.17763.4010; 10.0.20348.0 < 10.0.20348.1547; 10.0.0 < 10.0.19042.2604; 10.0.0 < 10.0.22621.1574; 10.0.19043.0 < 10.0.19044.2604 · 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 < 10.0.10240.19747; 10.0.14393.0 < 10.0.14393.5717; 10.0.17763.0 < 10.0.17763.4010; 10.0.0 < 10.0.17763.4010; 10.0.0 < 10.0.19042.2604; 10.0.19043.0 < 10.0.19044.2604; 10.0.19045.0 < 10.0.19045.2604; 10.0.0 < 10.0.22621.1574 · 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 ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Fixed release or patch reference recorded
ENISA EUVD · EUVD-2023-25986↗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.
Free version - for non-commercial use only.CVE-2023-21820 · cve.blacktree.nl