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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Obtain low-privileged local session
  2. Delivery
    Craft or obtain malicious Word document
  3. Exploit
    Open document to trigger UAF in Word memory allocator
  4. Execution
    Read freed heap memory contents
  5. Impact
    Exfiltrate disclosed sensitive data locally

Vulnerability Assessment

Weakness
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Memory lifecycle management
MITRE ATT&CK

2 techniques across 2 tactics: Execution, Privilege Escalation

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

Exploitation requires an authenticated local session on an affected Windows host (PR:L, AV:L). The attacker must be able to open or cause Word to process a crafted document - achievable by any low-privileged user account with access to the application. No special non-default configuration is required beyond having Microsoft Office Word installed and running on an affected Windows build. Limiting factors: AV:L means no remote unauthenticated exploitation; I:N and A:N mean there is no write primitive or denial-of-service capability; S:U means no lateral movement through scope change. The primary constraint is the requirement for an existing local authenticated session.

Impact

Real-world risk is moderate. CVSS 5.5 (medium) accurately reflects a locally-bounded, confidentiality-only flaw with low-privilege prerequisites - not an internet-facing threat. EPSS data is absent from the provided input, so exploitation probability cannot be quantified; however, no CISA KEV listing and no public POC mean this does not currently meet criteria for emergency remediation. SSVC signals: exploitation status is 'none' (no KEV/POC), automatable is 'no' (AV:L, requires local session), technical impact is 'partial' (C:H but I:N/A:N). The 'Denial Of Service' tag in the input is contradicted by the CVSS vector (A:N) and description (information disclosure) - this tag is mislabeled. The mismatch between 'Microsoft Office Word' in the description and the Windows platform version strings in EUVD affected versions introduces uncertainty about whether patching Word via Office Update or Windows Update is the correct remediation path; defenders should apply both channels.

Exploit ScenarioDerived

A low-privileged local user on an unpatched Windows system opens a specially crafted Word document that triggers a use-after-free condition in the document-processing code path. The freed heap memory, which may contain cached credential fragments, document contents, or other sensitive in-process data, becomes readable before it is overwritten, and the attacker reads the disclosed contents. No public exploit code exists at time of analysis, so this scenario requires bespoke exploitation knowledge.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
Patch available 0.3% exploitation probability (EPSS)

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AnalysisAIv1 – Sep 09, 2026

Use-after-free (CWE-416) in Microsoft Office Word enables a locally authenticated attacker to disclose sensitive memory contents. Exploitation requires only low-privileged local access with no user interaction, yielding high confidentiality impact per the CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N vector. No public exploit or active exploitation has been identified at time of analysis, and a vendor-released patch is available through Microsoft's update mechanism.

RemediationAI

Apply the vendor-released patch via Microsoft Update. For Windows platforms, update to the fixed builds listed in the EUVD affected-versions data (e.g., Windows 11 24H2 → 10.0.26100.9445, Windows Server 2025 → 10.0.26100.33438 - full list at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-68843). Because the description attributes the flaw to Microsoft Office Word while the version data references Windows, administrators should also ensure Office/Microsoft 365 applications are patched via Microsoft Update or the Office Deployment Tool. As a compensating control for systems where patching is temporarily infeasible, restrict local user access to Word document processing on sensitive systems and limit the ability of low-privileged accounts to open untrusted documents. No workaround fully replaces the patch for a UAF-class memory flaw.

Affected VersionsENISA

Windows Server 2019 (Server Core installation) 10.0.17763.0 <10.0.17763.9245
Windows Server 2012 R2 (Server Core installation) 6.3.9600.0 <6.3.9600.23397
Windows Server 2012 6.2.9200.0 <6.2.9200.26349
Windows Server 2016 10.0.14393.0 <10.0.14393.9512
Windows Server 2022 10.0.20348.0 <10.0.20348.5622
Windows Server 2019 10.0.17763.0 <10.0.17763.9245
Windows Server 2012 (Server Core installation) 6.2.9200.0 <6.2.9200.26349
Windows Server 2012 R2 6.3.9600.0 <6.3.9600.23397
Windows Server 2016 (Server Core installation) 10.0.14393.0 <10.0.14393.9512
Windows Server 2025 (Server Core installation) 10.0.26100.0 <10.0.26100.33438
Windows 11 version 26H1 10.0.28000.0 <10.0.28000.2954
Windows 10 Version 1809 10.0.17763.0 <10.0.17763.9245
Windows Server 2025 10.0.26100.0 <10.0.26100.33438
Windows 11 Version 25H2 10.0.26200.0 <10.0.26200.9445
Windows 11 Version 23H2 10.0.22631.0 <10.0.22631.7582
Windows 10 Version 1607 10.0.14393.0 <10.0.14393.9512
Windows 11 Version 24H2 10.0.26100.0 <10.0.26100.9445
Windows 10 Version 22H2 10.0.19045.0 <10.0.19045.7725
Windows 10 Version 21H2 10.0.19044.0 <10.0.19044.7725

Affected Packages

euvd windows_10_version_1607 fix: 10.0.14393.9512
euvd windows_10_version_1809 fix: 10.0.17763.9245
euvd windows_10_version_21h2 fix: 10.0.19044.7725
euvd windows_10_version_22h2 fix: 10.0.19045.7725
euvd windows_11_version_23h2 fix: 10.0.22631.7582
euvd windows_11_version_24h2 fix: 10.0.26100.9445
euvd windows_11_version_25h2 fix: 10.0.26200.9445
euvd windows_11_version_26h1 fix: 10.0.28000.2954
euvd windows_server_2012 fix: 6.2.9200.26349
euvd windows_server_2012_r2 fix: 6.3.9600.23397
euvd windows_server_2012_r2_server_core_installation fix: 6.3.9600.23397
euvd windows_server_2012_server_core_installation fix: 6.2.9200.26349
euvd windows_server_2016 fix: 10.0.14393.9512
euvd windows_server_2016_server_core_installation fix: 10.0.14393.9512
euvd windows_server_2019 fix: 10.0.17763.9245
euvd windows_server_2019_server_core_installation fix: 10.0.17763.9245
euvd windows_server_2022 fix: 10.0.20348.5622
euvd windows_server_2025 fix: 10.0.26100.33438
euvd windows_server_2025_server_core_installation fix: 10.0.26100.33438

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 19 packages in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

CWE-416 (Use After Free) occurs when a program continues to use a pointer to heap memory after that memory has been freed, allowing an attacker to read stale contents before the allocator overwrites them or to influence what data appears in that location. In Microsoft Office Word, this flaw resides in a document-processing code path accessible to a low-privileged local user. The CVSS vector confirms local attack vector (AV:L), no scope change (S:U), and no integrity or availability impact - consistent with a read-primitive that leaks freed heap memory rather than enabling code execution. A significant data-quality discrepancy is present: the EUVD-sourced affected-versions list enumerates Windows platform builds (Windows 10/11, Windows Server 2012-2025) rather than Office/Word version numbers, suggesting the UAF may reside in a shared Windows component (e.g., a system DLL consumed by Word) whose patch is delivered via Windows Update, or that the version data was pulled from the wrong advisory record.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (microsoft) PRIMARY 5.5 MEDIUM
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
vuln.today AI 5.5 MEDIUM

Local access only, low privilege (authenticated user session), no scope change; purely a read primitive with no integrity or availability impact.

3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
4.0 AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

Primary rating from Vendor (microsoft).

CVSS VectorVendor: microsoft

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

Lifecycle Timeline

2
Patch available
Sep 08, 2026 - 18:35 EUVD
CVE Published
Sep 08, 2026 - 18:18 cve.org
MEDIUM 5.5

DescriptionCVE.org

Use after free in Microsoft Office Word allows an authorized attacker to disclose information locally.

Threat Intelligence Overview

EPSS Score
0.3%
Top 77% exploitable
Prevalence
High
Microsoft Office/Word deployed across most enterprise environments globally
Vendor Status
Publicly Disclosed:No
Exploited:No
Latest Software Release:Exploitation Less Likely
Data Quality
5 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 0.3%
Patch available Yes
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Defer
Exploitation
None
System Exposure· derived
Small
Automatable
No
Human Impact· derived
Medium
Technical Impact
Partial

Priority Score

28
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +28
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Use-after-free vulnerabilities occur when a program continues to access memory through a pointer after that memory has been deallocated.

Memory corruption occurs when a program writes data beyond the boundaries of allocated memory regions or accesses memory in unintended ways, violating the integrity of the process's address space.

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