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Full vulnerability report · 2021
CVE-2021-27094High confidence

Windows Early Launch Antimalware Driver Security Feature Bypass Vulnerability

Microsoft · Windows 10 Version 1803

4.4MediumCVSS 3.1
Recommended action
Within 7 days

Medium technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.

Patch available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityMediumOperational priority:Medium, unchanged from published severity.unchanged

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • A structured source references public exploit or proof-of-concept material.
  • Exploitation requires an existing local or physical foothold with privileges.
  • EPSS is 0.97% 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 10 Version 1803 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: As exposure requiresRemediation target: Within 365 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-2021-13865

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

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
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

Medium technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.

Patch available
01

What, why and how

Windows Early Launch Antimalware Driver Security Feature Bypass Vulnerability

What

Windows Early Launch Antimalware Driver Security Feature Bypass 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 cause the confidentiality, integrity or availability impact described by the vendor.

What

Windows Early Launch Antimalware Driver Security Feature Bypass 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 cause the confidentiality, integrity or availability impact described by the vendor.

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.
Reference recorded

A structured CVE source labels at least one public reference as exploit material. BlackTree has not independently validated that it is safe, reliable or weaponised.

Likely attack path
local access → vulnerable operation → cause the confidentiality, integrity or availability impact described by the vendor
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:N/I:H/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.CNoneConfidentiality impact: No direct loss is represented by this metric.IHighIntegrity impact: A successful attack can cause a major loss.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.
Public exploit reference
A

Official authority intelligence

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

Cyber Security Agency of Singapore · English · CSA-SB-20210414Security Bulletin 14 Apr 2021

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 14 Apr 2021, published on 14 April 2021. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2021-AVI-261Multiples vulnérabilités dans Microsoft Windows

d?id=CVE-2021-27072 Référence CVE CVE-2021-27079 https://www.cve.org/CVERecord?id=CVE-2021-27079 Référence CVE CVE-2021-27086 https://www.cve.org/CVERecord?id=CVE-2021-27086 Référence CVE CVE-2021-27088 https://www.cve.org/CVERecord?id=CVE-2021-27088 Référence CVE CVE-2021-27089 https://www.cve.org/CVERecord?id=CVE-2021-27089 Référence CVE CVE-2021-27090 https://www.cve.org/CVERecord?id=CVE-2021-27090 Référence CVE CVE-2021-27091 https://www.cve.org/CVERecord?id=CVE-2021-27091 Référence CVE CVE-2021-27092 https://www.cve.org/CVERecord?id=CVE-2021-27092 Référence CVE CVE-2021-27093 https://www.cve.org/CVERecord?id=CVE-2021-27093 Référence CVE CVE-2021-27094 https://www.cve.org/CVERecord?id=CVE-2021-27094 Référence CVE CVE-2021-27095 https://www.cve.org/CVERecord?id=CVE-2021-27095 Référence CVE CVE-2021-27096 https://www.cve.org/CVERecord?id=CVE-2021-27096 Référence CVE CVE-2021-28309 https://www.cve.org/CVERecord?id=CVE-2021-28309 Référence CVE CVE-2021-28310 https://www.cve.org/CVERecord?id=CVE-2021-28310 Référence CVE CVE-2021-28311 https://www.cve.org/CVERecord?id=CVE-2021-28311 Référence CVE CVE-2021-28312 https://www.cve.org/CVERecord?id=CVE-2021-28312 Référence CVE CVE-2021-28313 https://www.cve.org/CVERecord?id=CVE-2021-28313 Référence CVE CVE-2021-28314 https://www.cve.org/CVERecord?id=

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2021-001492複数の Microsoft Windows 製品におけるセキュリティ機能を回避される脆弱性

複数の Microsoft Windows 製品には、Windows Early Launch Antimalware ドライバに不備があるため、セキュリティ機能を回避される脆弱性が存在します。 本脆弱性は、CVE-2021-28447 とは異なる脆弱性です。

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2021-001403複数の Microsoft Windows 製品におけるセキュリティ機能を回避される脆弱性

複数の Microsoft Windows 製品には、Windows Early Launch Antimalware ドライバに不備があるため、セキュリティ機能を回避される脆弱性が存在します。 本脆弱性は、CVE-2021-27094 とは異なる脆弱性です。

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-5297MS 4월 보안 위협에 따른 정기 보안 업데이트 권고

2 Java용 Visual Studio Code Maven 확장 원격 코드 실행 취약성 Windows Application Compatibility Cache CVE-2021-28311 Windows 응용 프로그램 호환성 캐시 서비스 거부 취약성 Windows AppX Deployment Extensions CVE-2021-28326 Windows AppX 배포 서버 서비스 거부 취약성 Windows Console Driver CVE-2021-28443 Windows 콘솔 드라이버 서비스 거부 취약성 Windows Console Driver CVE-2021-28438 Windows 콘솔 드라이버 서비스 거부 취약성 Windows Diagnostic Hub CVE-2021-28322 진단 허브 표준 수집기 서비스 권한 상승 취약성 Windows Diagnostic Hub CVE-2021-28321 진단 허브 표준 수집기 서비스 권한 상승 취약성 Windows Diagnostic Hub CVE-2021-28313 진단 허브 표준 수집기 서비스 권한 상승 취약성 Windows Early Launch Antimalware Driver CVE-2021-28447 Windows 조기 실행 맬웨어 방지 드라이버 보안 기능 우회 취약성 Windows ELAM CVE-2021-27094 Windows 조기 실행 맬웨어 방지 드라이버 보안 기능 우회 취약성 Windows Event Tracing CVE-2021-28435 Windows 이벤트 추적 정보 유출 취약성 Windows Event Tracing CVE-2021-27088 Windows 이벤트 추적 권한 상승 취약성 Windows Installer CVE-2021-28440 Windows Installer 권한 상승 취약성 Windows Installer CVE-2021-28437 Windows 설치 관리자 정보 유출 취약성 Windows Installer CVE-2021-26415 Windows Installer 권한 상승 취약성 Windows Installer CVE-2021-26413 Windows 설치 관리자 스푸핑 취약성 Windows Kernel CVE-2021-28309 Windows 커널 정보 유출 취약성 Windows Kernel CVE-2021-27093 Windows 커널 정보 유출 취약성 Windows Media Player CVE-2021-28315 Windows Media 비디오 디코더 원격 코드 실행 취약성 Windows Media Player CVE-2021-27095 Windows Media 비디오 디코더 원격 코드 실행 취약성 Window

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 13 Apr 2021 · Last source change 3 Aug 2024, 20:40 UTC · CWE not yet assigned

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-2021-13865
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 ↗

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

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-2021-13865↗CVE authority or vendor reference↗Public exploit 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-2021-27094 · cve.blacktree.nl