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Full vulnerability report · 2023
CVE-2023-21674High confidence

Microsoft Windows Advanced Local Procedure Call (ALPC) Privilege Escalation Vulnerability

Microsoft · Windows

8.8HighCVSS 3.1
Recommended action
Patch now

CISA confirms exploitation in the wild and lists 2023-01-31 as the remediation due date.

Patch available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityHighOperational priority:Critical, raised one band.upgradedsince 10 Jan 2023

Evidence used

  • CISA confirms exploitation in the wild.
  • Exploitation requires an existing local or physical foothold with privileges.
  • EPSS is 40.99% 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.
  • Increase monitoring for the attack path and post-exploitation behaviour described in the report.

Verification

  1. Confirm that the asset runs Microsoft Windows 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 3 daysRemediation target: Within 90 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-2023-25841

CISA KEV mirrored by ENISA

Windows Advanced Local Procedure Call (ALPC) Elevation of Privilege Vulnerability

EUVD state
Present in the current official mapping
Known exploitation
Recorded by ENISA since 10 Jan 2023. Evidence sources: cisa_kev.
ENISA score
8.8 · CVSS 3.1
Advisory evidence
2 linked advisory records
Recommended actionPatch now

CISA confirms exploitation in the wild and lists 2023-01-31 as the remediation due date.

Patch available
01

What, why and how

Microsoft Windows Advanced Local Procedure Call (ALPC) contains an unspecified vulnerability that allows for privilege escalation.

What

Microsoft Windows Advanced Local Procedure Call (ALPC) contains an unspecified vulnerability that allows for privilege escalation.

Why

The program can continue using memory after it has been released, producing unsafe and attacker-influenceable behaviour.

How

An attacker operating through local access may attempt exploitation with low privileges. If successful, the issue may gain additional privileges.

What

Microsoft Windows Advanced Local Procedure Call (ALPC) contains an unspecified vulnerability that allows for privilege escalation.

Why

The program can continue using memory after it has been released, producing unsafe and attacker-influenceable behaviour.

How

An attacker operating through local access may attempt exploitation with low privileges. If successful, the issue may gain additional privileges.

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.
Confirmed in the wild

CISA added this CVE to its Known Exploited Vulnerabilities catalogue on 2023-01-10.

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 → Use After Free → gain additional privileges
Attack surface
Local
Privileges required
Low: a basic authenticated account is required
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Changed: exploitation can affect a different security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-416 ↗

CWE-416: Use After Free. The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.

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:L/UI:N/S:C/C:H/I:H/A:H/E:F/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.PRLowPrivileges required: The attacker needs basic user-level privileges.UINoneUser interaction: No action by another user is required.SChangedScope: The attack can affect a component governed by a different security 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
The issue can support a local privilege or sandbox boundary transition; normal system utilities may then be available in the gained context.
Privilege escalationCWE-416CISA KEV
A

Official authority intelligence

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

ENISA EUVD · EUVD-2023-25841Known-exploited evidence recorded

Windows Advanced Local Procedure Call (ALPC) Elevation of Privilege Vulnerability

Official EUVD record ↗
BSI · German · WID-SEC-2023-0055Microsoft Windows und Microsoft Windows Server: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in Microsoft Windows und Microsoft Windows Server ausnutzen, um beliebigen Code auszuführen, Sicherheitsmaßnahmen zu umgehen, vertrauliche Informationen offenzulegen, seine Privilegien zu erweitern und einen Denial-of-Service-Zustand auszulösen.

Official advisory ↗
Canadian Centre for Cyber Security · English · AV23-016Microsoft security advisory – January 2023 monthly rollup (AV23-016)

On January 10, 2023, Microsoft published security updates to address vulnerabilities in multiple products. Included were critical updates for the following: Microsoft has indicated that CVE-2023-21674 has been actively exploited.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20230111Security Bulletin 11 Jan 2023

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 11 Jan 2023, published on 11 January 2023. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2023-AVI-0022Multiples vulnérabilités dans Microsoft Windows

janvier 2023 https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21558 Bulletin de sécurité Microsoft CVE-2023-21559 du 10 janvier 2023 https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21559 Bulletin de sécurité Microsoft CVE-2023-21560 du 10 janvier 2023 https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21560 Bulletin de sécurité Microsoft CVE-2023-21561 du 10 janvier 2023 https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21561 Bulletin de sécurité Microsoft CVE-2023-21563 du 10 janvier 2023 https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21563 Bulletin de sécurité Microsoft CVE-2023-21674 du 10 janvier 2023 https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21674 Bulletin de sécurité Microsoft CVE-2023-21675 du 10 janvier 2023 https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21675 Bulletin de sécurité Microsoft CVE-2023-21676 du 10 janvier 2023 https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21676 Bulletin de sécurité Microsoft CVE-2023-21677 du 10 janvier 2023 https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21677 Bulletin de sécurité Microsoft CVE-2023-21678 du 10 janvier 2023 https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21678 Bulletin de sécurité Micr

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2023-001106複数の Microsoft Windows 製品における権限を昇格される脆弱性

複数の Microsoft Windows 製品には、Windows Advanced Local Procedure Call (ALPC) に不備があるため、権限を昇格される脆弱性が存在します。

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-5823MS 1월 보안 위협에 따른 정기 보안 업데이트 권고

점간 프로토콜) 정보 공개 취약점 Microsoft WDAC OLE DB provider for SQL CVE-2023-21681 SQL Server 원격 코드 실행 취약점에 대한 Microsoft WDAC OLE DB 공급자 Microsoft Graphics Component CVE-2023-21680 Windows Win32k 권한 상승 취약점 Windows Layer 2 Tunneling Protocol CVE-2023-21679 Windows 레이어 2 터널링 프로토콜(L2TP) 원격 코드 실행 취약점 Windows Print Spooler Components CVE-2023-21678 Windows 인쇄 스풀러 권한 상승 취약점 Windows IKE Extension CVE-2023-21677 Windows 인터넷 키 교환(IKE) 확장 서비스 거부 취약점 Windows LDAP - Lightweight Directory Access Protocol CVE-2023-21676 Windows LDAP(Lightweight Directory Access Protocol) 원격 코드 실행 취약점 Windows Virtual Registry Provider CVE-2023-21675 Windows 커널 권한 상승 취약점 Windows ALPC CVE-2023-21674 Windows 고급 로컬 프로시저 호출(ALPC) 권한 상승 취약점 Windows BitLocker CVE-2023-21563 BitLocker 보안 기능 우회 취약점 Windows Cryptographic Services CVE-2023-21561 Microsoft Cryptographic Services 권한 상승 취약점 Windows Boot Manager CVE-2023-21560 Windows 부팅 관리자 보안 기능 우회 취약점 Windows Cryptographic Services CVE-2023-21559 Windows 암호화 정보 공개 취약점 Windows Error Reporting CVE-2023-21558 Windows 오류 보고 서비스 권한 상승 취약점 Windows LDAP - Lightweight Directory Access Protocol CVE-2023-21557 Windows LDAP(Lightweight Directory Access Protocol) 서비스 거부 취약점 Windows Layer 2 Tunneling Protocol CVE-2023-21556 Windows 레이어 2 터널링 프로토콜(L2TP) 원격 코드 실행 취약점 Windows Layer 2 Tunneling Protocol CVE-2023-

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-5822현재 악용되고 있는 Exploit(Update. 2023-01-10)

Microsoft Windows Advanced Local Procedure Call (ALPC) contains an unspecified vulnerability that allows for privilege escalation.

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 10 Jan 2023 · Last source change 21 Oct 2025, 23:15 UTC · CWE-416 · Use After Free

CVE recordCVE.org · 5.1
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-2023-25841
Product sourceCISA KEV
Remediation sourceCVE/CNA references
CWE sourceOther authority
NVD statusNVD enriched

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 < 10.0.17763.3887; 10.0.0 < 10.0.17763.3887; 10.0.20348.0 < 10.0.20348.1487; 10.0.0 < 10.0.19042.2486; 10.0.0 < 10.0.22000.1455; 10.0.19043.0 < 10.0.19044.2486 · 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
    Windows 10 Version 1809: 10.0.17763.0 < 10.0.17763.3887, 10.0.0 < 10.0.17763.3887; Windows Server 2019: 10.0.17763.0 < 10.0.17763.3887; Windows Server 2019 (Server Core installation): 10.0.17763.0 < 10.0.17763.3887; Windows Server 2022: 10.0.20348.0 < 10.0.20348.1487; Windows 10 Version 20H2: 10.0.0 < 10.0.19042.2486; Windows 11 version 21H2: 10.0.0 < 10.0.22000.1455; Windows 10 Version 21H2: 10.0.19043.0 < 10.0.19044.2486; Windows 11 version 22H2: 10.0.22621.0 < 10.0.22621.1105; Windows 10 Version 22H2: 10.0.19045.0 < 10.0.19045.2486; Windows 10 Version 1507: 10.0.10240.0 < 10.0.10240.19685; Windows 10 Version 1607: 10.0.14393.0 < 10.0.14393.5648; Windows Server 2016: 10.0.14393.0 < 10.0.14393.5648; Windows Server 2016 (Server Core installation): 10.0.14393.0 < 10.0.14393.5648; Windows 8.1: 6.3.0 < 6.3.9600.20778; Windows Server 2012 R2: 6.3.9600.0 < 6.3.9600.20778; Windows Server 2012 R2 (Server Core installation): 6.3.9600.0 < 6.3.9600.20778 · 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
Added to CISA KEV
Fixed release or patch reference recorded
ENISA EUVD · EUVD-2023-25841↗CISA KEV record↗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-2023-21674 · cve.blacktree.nl