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Full vulnerability report · 2026
CVE-2026-21514High confidence

Microsoft Office Word Reliance on Untrusted Inputs in a Security Decision Vulnerability

Microsoft · Office

7.8HighCVSS 3.1
Recommended action
Patch now

CISA confirms exploitation in the wild and lists 2026-03-03 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 Feb 2026

Evidence used

  • CISA confirms exploitation in the wild.
  • EPSS is 1.58% 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 Office 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-2026-7334

CISA KEV mirrored by ENISA

Reliance on untrusted inputs in a security decision in Microsoft Office Word allows an unauthorized attacker to bypass a security feature locally.

EUVD state
Present in the current official mapping
Known exploitation
Recorded by ENISA since 10 Feb 2026. Evidence sources: cisa_kev.
ENISA score
7.8 · CVSS 3.1
Advisory evidence
3 linked advisory records
Explicit mitigation evidence

Only statements that explicitly mention a fix, patch, update, workaround or mitigation are shown here.

  • csaf_ncscnl · NCSC-2026-0058Kwetsbaarheden verholpen in Microsoft Office
Recommended actionPatch now

CISA confirms exploitation in the wild and lists 2026-03-03 as the remediation due date.

Patch available
01

What, why and how

Microsoft Office Word contains a reliance on untrusted inputs in a security decision vulnerability that could allow an authorized attacker to elevate privileges locally.

What

Microsoft Office Word contains a reliance on untrusted inputs in a security decision vulnerability that could allow an authorized attacker to elevate privileges locally.

Why

The product uses a protection mechanism that relies on the existence or values of an input, but the input can be modified by an untrusted actor in a way that bypasses the protection mechanism.

How

An attacker operating through local access may attempt exploitation without authentication after a user interaction. If successful, the issue may gain additional privileges.

What

Microsoft Office Word contains a reliance on untrusted inputs in a security decision vulnerability that could allow an authorized attacker to elevate privileges locally.

Why

The product uses a protection mechanism that relies on the existence or values of an input, but the input can be modified by an untrusted actor in a way that bypasses the protection mechanism.

How

An attacker operating through local access may attempt exploitation without authentication after a user interaction. 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 2026-02-10.

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 → Reliance on Untrusted Inputs in a Security Decision → gain additional privileges
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: a standard category for the underlying weakness.
CWE-807 ↗

CWE-807: Reliance on Untrusted Inputs in a Security Decision. The product uses a protection mechanism that relies on the existence or values of an input, but the input can be modified by an untrusted actor in a way that bypasses the protection mechanism.

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: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.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
The issue can support a local privilege or sandbox boundary transition; normal system utilities may then be available in the gained context.
UnauthenticatedPrivilege escalationCWE-807CISA KEV
A

Official authority intelligence

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

ENISA EUVD · EUVD-2026-7334Known-exploited evidence recorded

Reliance on untrusted inputs in a security decision in Microsoft Office Word allows an unauthorized attacker to bypass a security feature locally.

Official EUVD record ↗
BSI · German · WID-SEC-2026-0371Microsoft Office: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in Microsoft Excel, Microsoft Word, Microsoft Outlook, Microsoft Office Online Server, Microsoft SharePoint, Microsoft Office, Microsoft SharePoint Server 2019 und Microsoft 365 Apps ausnutzen, um Administratorrechte zu erlangen, Spoofing-Angriffe durchzuführen, Sicherheitsmaßnahmen zu umgehen und vertrauliche Informationen offenzulegen.

Official advisory ↗
Canadian Centre for Cyber Security · English · AV26-111Microsoft security advisory – February 2026 monthly rollup (AV26-111) - Update 1

On February 10, 2026, Microsoft published security advisories to address vulnerabilities in multiple products. Included were critical updates for the following products: Microsoft has received reports that CVE-2026-21525, CVE-2026-21514, CVE-2026-21510, CVE-2026-21513, CVE-2026-21533 and CVE-2026-21519 are being exploited.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20260211Security Bulletin 11 Feb 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 11 Feb 2026, published on 11 February 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-0149Multiples vulnérabilités dans Microsoft Office

De multiples vulnérabilités ont été découvertes dans Microsoft Office. Elles permettent à un attaquant de provoquer une élévation de privilèges, une atteinte à la confidentialité des données et un contournement de la politique de sécurité. Microsoft indique que la vulnérabilité CVE-2026-21514 est activement exploitée.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2026-003529マイクロソフトのMicrosoft 365 Apps等の複数製品におけるセキュリティ決定の信頼できない入力への依存に関する脆弱性

Microsoft Office Wordにおけるセキュリティ判断が信頼されていない入力に依存しているため、不正な攻撃者がローカル環境でセキュリティ機能を回避できる問題があります。

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-6688MS 2월 보안 위협에 따른 정기 보안 업데이트 권고

26-21523 | GitHub Copilot 및 Visual Studio Code 원격 코드 실행 취약성 | | Azure Compute Gallery | CVE-2026-21522 | Microsoft ACI 기밀 컨테이너 권한 상승 취약성 | | Copilot | CVE-2026-21521 | Word Copilot Information Disclosure Vulnerability | | Copilot Studio | CVE-2026-21520 | Copilot Studio 정보 공개 취약성 | | Desktop Window Manager | CVE-2026-21519 | 데스크톱 Windows 관리자 권한 상승 취약성 | | GitHub Copilot and Visual Studio Code | CVE-2026-21518 | GitHub Copilot 및 Visual Studio Code 보안 기능 바이패스 취약성 | | Windows App for Mac | CVE-2026-21517 | Mac용 Windows 앱 설치 프로그램 권한 상승 취약성 | | Github Copilot | CVE-2026-21516 | GitHub Copilot for Jetbrains 원격 코드 실행 취약성 | | Microsoft Office Word | CVE-2026-21514 | Microsoft Word 보안 기능 우회 취약성 | | MSHTML Framework | CVE-2026-21513 | MSHTML Framework Security Feature Bypass Vulnerability | | Azure DevOps Server | CVE-2026-21512 | Azure DevOps Server 교차 사이트 스크립팅 취약성 | | Microsoft Office Outlook | CVE-2026-21511 | Microsoft Outlook 스푸핑 취약성 | | Windows Shell | CVE-2026-21510 | Windows Shell 보안 기능 바이패스 취약성 | | Microsoft Office | CVE-2026-21509 | Microsoft Office 보안 기능 우회 취약성 | | Windows Storage | CVE-2026-21508 | Windows 저장소 권한 상승 취약성 | | Microsoft Account | CVE-2026-21264 | Microsoft Account Spoofing Vulnerability | | Microsoft Office Excel | CVE-2026-21261 | Microsoft Excel 정보 유출 취약성 | | Microsoft Office

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-6686美 CISA 발표 주요 Exploit 정보공유(Update. 2026-02-10)

Microsoft Office Word contains a reliance on untrusted inputs in a security decision vulnerability that could allow an authorized attacker to elevate privileges locally.

Official advisory ↗
NCSC-NL · Dutch · NCSC-2026-0058Kwetsbaarheden verholpen in Microsoft Office

Een kwaadwillende kan de kwetsbaarheden misbruiken om beveiligingsmaatregelen te omzeilen, zoch voor te doen als andere gebruiker en zich zo verhoogde rechten toe te kennen en toegang te krijgen tot gevoelige gegevens. Voor succesvol misbruik moet de kwaadwillende het slachtoffer misleiden en malafide bestand te openen of link te volgen. Van de kwetsbaarheid met kenmerk CVE-2026-21511 meldt Microsoft informatie te hebben dat deze besproken wordt op fora. De kwetsbaarheid stelt een kwaadwillende in staat om middels een malafide bericht een NTLM-authenticatie te initiëren naar een server onder controle van de kwaadwillende, waarmee de kwaadwillende authenticatiegegevens kan bemachtigen. Er is (nog) geen publieke Proof-of-Concept-code beschikbaar en misbruik vereist een speciaal ingerichte server. Grootschalig misbruik is hiermee niet waarschijnlijk. ``` Microsoft Office Word: |----------------|------|-------------------------------------| | CVE-ID | CVSS | Impact | |----------------|------|-------------------------------------| | CVE-2026-21514 | 7.80 | Omzeilen van beveiligingsmaatregel | |----------------|------|-------------------------------------| Microsoft Office Excel: |----------------|------|-------------------------------------| | CVE-ID | CVSS | Impact | |----------------|------|-------------------------------------| | CVE-2026-21259 | 7.30 | Verkrijgen van verhoogde rechten | | CVE-2026-21258 | 5.50 | Toegang tot gevoelige gegevens | | CVE-2026-21261 | 5.50 | Toegang tot gevoelige gegevens | |----------------|------|-------------------------------------| Microsoft Office Outlook: |----------------|------|-------------------------------------| | CVE-ID | CVSS | Impact | |----------------|------|-------------------------------------| | CVE-2026-21260 | 7.50 | Voordoen als andere gebruiker | | CVE-2026-21511 | 7.50 | Voordoen als andere gebruiker | |----------------|------|-------------------------------------| ```

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 Feb 2026 · Last source change 19 Aug 2026, 16:26 UTC · CWE-807 · Reliance on Untrusted Inputs in a Security Decision

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-2026-7334
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. BlackTree coverageBlackTree article coverage changed from no BlackTree article to 1 BlackTree article.
    Before
    no BlackTree article
    After
    1 BlackTree article
    BlackTree editorial ↗
  2. Vendor guidanceAuthoritative vendor guidance changed: removed remediation: cyber.gc.ca/microsoft-security-advisory-february-2026-monthly-rollup-av26-111.
    Before
    remediation: cyber.gc.ca/microsoft-security-advisory-february-2026-monthly-rollup-av26-111 · vendor advisory: msrc.microsoft.com/CVE-2026-21514
    After
    vendor advisory: msrc.microsoft.com/CVE-2026-21514
    secure@microsoft.com ↗
  3. Remediation statusRemediation status changed from Mitigation available to Awaiting fix.
    Before
    Mitigation available
    After
    Awaiting fix
    secure@microsoft.com ↗
  4. Affected versionsThe structured affected or fixed version information changed.
    Before
    16.0.1 < https://aka.ms/OfficeSecurityReleases; 16.0.0 < https://aka.ms/OfficeSecurityReleases; 16.0.1 < 16.106.26020821; 16.0.0 < 16.106.26020821 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    After
    Microsoft 365 Apps for Enterprise: 16.0.1 < https://aka.ms/OfficeSecurityReleases; Microsoft Office LTSC 2021: 16.0.1 < https://aka.ms/OfficeSecurityReleases; Microsoft Office LTSC 2024: 16.0.0 < https://aka.ms/OfficeSecurityReleases; Microsoft Office LTSC for Mac 2021: 16.0.1 < 16.106.26020821; Microsoft Office LTSC for Mac 2024: 16.0.0 < 16.106.26020821 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    CNA ↗
  5. Remediation statusRemediation status changed from Awaiting fix to Mitigation available.
    Before
    Awaiting fix
    After
    Mitigation available
    Canadian Centre for Cyber Security ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Added to CISA KEV
ENISA EUVD · EUVD-2026-7334↗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-2026-21514 · cve.blacktree.nl