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Full vulnerability report · 2021
CVE-2021-36937High confidence

Windows Media MPEG-4 Video Decoder Remote Code Execution Vulnerability

Microsoft · Windows 10 Version 1507

7.8HighCVSS 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 2.30% 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-2021-23513

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

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

Patch available
01

What, why and how

Windows Media MPEG-4 Video Decoder Remote Code Execution Vulnerability

What

Windows Media MPEG-4 Video Decoder Remote Code Execution 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 without authentication after a user interaction. If successful, the issue may execute code or commands in the affected security context.

What

Windows Media MPEG-4 Video Decoder Remote Code Execution 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 without authentication after a user interaction. 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
local access → vulnerable operation → execute code or commands in the affected security context
Attack surface
Local
Privileges required
None: unauthenticated exploitation is possible
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.
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:N/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.

AVLocalAttack vector: The attacker needs local access to the vulnerable system.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing 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.
UnauthenticatedRemote code execution
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-20210818Security Bulletin 18 Aug 2021

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 18 Aug 2021, published on 18 August 2021. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2021-AVI-618Multiples vulnérabilités dans Microsoft Windows

d?id=CVE-2021-34534 Référence CVE CVE-2021-34535 https://www.cve.org/CVERecord?id=CVE-2021-34535 Référence CVE CVE-2021-34536 https://www.cve.org/CVERecord?id=CVE-2021-34536 Référence CVE CVE-2021-34537 https://www.cve.org/CVERecord?id=CVE-2021-34537 Référence CVE CVE-2021-36926 https://www.cve.org/CVERecord?id=CVE-2021-36926 Référence CVE CVE-2021-36927 https://www.cve.org/CVERecord?id=CVE-2021-36927 Référence CVE CVE-2021-36932 https://www.cve.org/CVERecord?id=CVE-2021-36932 Référence CVE CVE-2021-36933 https://www.cve.org/CVERecord?id=CVE-2021-36933 Référence CVE CVE-2021-36936 https://www.cve.org/CVERecord?id=CVE-2021-36936 Référence CVE CVE-2021-36937 https://www.cve.org/CVERecord?id=CVE-2021-36937 Référence CVE CVE-2021-36938 https://www.cve.org/CVERecord?id=CVE-2021-36938 Référence CVE CVE-2021-36942 https://www.cve.org/CVERecord?id=CVE-2021-36942 Référence CVE CVE-2021-36945 https://www.cve.org/CVERecord?id=CVE-2021-36945 Référence CVE CVE-2021-36947 https://www.cve.org/CVERecord?id=CVE-2021-36947 Référence CVE CVE-2021-36948 https://www.cve.org/CVERecord?id=CVE-2021-36948 Gestion détaillée du document le 11 août 2021 Version initiale Alertes Avis Bulletins d’actualités Mentions légales Conditions générales À propos Contact cyber.gouv.fr service-public.fr legifrance.gouv.fr info.gouv.f

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2021-002293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

複数の Microsoft Windows 製品には、Windows Media MPEG-4 Video Decoder 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-5362MS 8월 보안 위협에 따른 정기 보안 업데이트 권고

021-36946 Microsoft Dynamics Business Central 교차-사이트 스크립팅 취약성 Microsoft Dynamics CVE-2021-34524 Microsoft Dynamics 365(온-프레미스) 원격 코드 실행 취약성 Microsoft Graphics Component CVE-2021-34533 Windows 그래픽 구성 요소 글꼴 구문 분석 원격 코드 실행 취약성 Microsoft Graphics Component CVE-2021-34530 Windows 그래픽 구성 요소 원격 코드 실행 취약성 Microsoft Office CVE-2021-34478 Microsoft Office 원격 코드 실행 취약성 Microsoft Office SharePoint CVE-2021-36940 Microsoft SharePoint Server 스푸핑 취약성 Microsoft Office Word CVE-2021-36941 Microsoft Word 원격 코드 실행 취약성 Microsoft Scripting Engine CVE-2021-34480 스크립팅 엔진 메모리 손상 취약성 Microsoft Windows CVE-2021-36934 Windows 권한 상승 취약성 Microsoft Windows Codecs Library CVE-2021-36937 Windows Media MPEG-4 비디오 디코더 원격 코드 실행 취약성 Remote Desktop Client CVE-2021-34535 원격 데스크톱 클라이언트 원격 코드 실행 취약성 Remote Desktop Connection Manager CVE-2020-0765 원격 데스크톱 연결 관리자 정보 유출 취약성 Windows Bluetooth Service CVE-2021-34537 Windows Bluetooth 드라이버 권한 상승 취약성 Windows Cryptographic Services CVE-2021-36938 Windows 암호화 기본 형식 라이브러리 정보 공개 취약성 Windows Defender CVE-2021-34471 Microsoft Windows Defender 권한 상승 취약성 Windows Event Tracing CVE-2021-34487 Windows 이벤트 추적 권한 상승 취약성 Windows Event Tracing CVE-2021-34486 Windows 이벤트 추적 권한 상승 취약성 Windows Event Tracing CVE-2021-26425 Windows 이벤트 추적 권한 상승 취약성 Windows Media CVE-2021-36927 Windows 디지털 TV 튜너 장치 등록 응용 프로그램

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 12 Aug 2021 · Last source change 10 Aug 2026, 15:10 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-2021-23513
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-2021-23513↗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.
Free version - for non-commercial use only.CVE-2021-36937 · cve.blacktree.nl