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Attack ChainAIDerived

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

  1. Access
    Deliver crafted Word document via phishing
  2. Delivery
    Victim opens malicious file
  3. Exploit
    Overflow stack buffer in Word parser
  4. Execution
    Execute arbitrary code as user
  5. Impact
    Full compromise of user context

Vulnerability Assessment

Weakness
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Stack buffer bounds checking
MITRE ATT&CK

1 technique across 1 tactic: Execution

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

Exploitation Conditions

Exploitation requires the victim to open a specially crafted Word document (UI:R) in an affected Office build - Microsoft 365 Apps for Enterprise, Office LTSC 2021/2024, or the corresponding Office for Mac / LTSC for Mac editions per the CPE list. No authentication or prior privileges are needed (PR:N), and attack complexity is low (AC:L), so no special non-default configuration is required beyond having a vulnerable Word version installed. The primary limiting factor is the mandatory user interaction: the attacker must socially-engineer the target into opening the malicious file, and Protected View / Mark-of-the-Web sandboxing may further impede exploitation of untrusted documents.

Impact

This is a genuine high priority. The CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:R) describes a remotely-reachable, low-complexity, unauthenticated code-execution flaw whose only gating factor is user interaction - the classic 'open a malicious Word document' pattern - and the high impact triple (C:H/I:H/A:H) reflects full compromise of the user's context. The 8.8 score is credible rather than inflated because no privileges are required and the affected product (Microsoft Office / Word) is deployed almost everywhere. However, key exploitation signals are MISSING from the input: there is no EPSS probability provided, no CISA KEV listing, no SSVC decision data, and no indication of public POC code - so real-world exploitation likelihood cannot be quantified from this data alone and must be treated as unconfirmed. The UI:R requirement meaningfully lowers the practical risk versus a zero-click RCE: exploitation depends on social engineering to make a victim open a crafted file. A vendor patch is confirmed available via MSRC, which is the single most actionable signal here. Net: treat as a high-priority patch-now item given ubiquity and the ease with which malicious Office documents are weaponized and phished, while noting that active-exploitation and POC status are unknown from the provided data.

Exploit ScenarioDerived

An attacker crafts a malicious Word document that triggers the stack-based buffer overflow when parsed and emails or otherwise delivers it to a target. When the victim opens the document, the overflow executes attacker-controlled code in the context of the user, enabling full compromise of that session. No public POC is identified in the provided data, and exploitation requires the victim to open the file (UI:R).

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
Patch available 0.4% exploitation probability (EPSS)

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AnalysisAIv1 – Oct 15, 2026

Remote code execution in Microsoft Word affects Microsoft 365 Apps for Enterprise, Office LTSC 2021/2024, and Office for Mac/LTSC for Mac editions, allowing an unauthenticated attacker to execute arbitrary code by convincing a victim to open a specially crafted document (UI:R). The stack-based buffer overflow (CWE-121) requires no privileges or non-default configuration (PR:N, AC:L), making it a high-priority target for social-engineering campaigns, though no public exploit code has been identified at time of analysis. Patch available per vendor advisory from the Microsoft Security Response Center.

RemediationAI

Patch available per vendor advisory: apply the latest updates through Microsoft Update, Microsoft 365 Apps update channels, or the Microsoft Update Guide for CVE-2026-108445 (https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-108445). Ensure all affected builds of Microsoft 365 Apps for Enterprise, Office LTSC 2021/2024, and Office for Mac/LTSC for Mac are updated; Microsoft's advisory lists the exact patched builds. Because exploitation requires the user to open a malicious document, enforce Protected View and Mark-of-the-Web for files from the internet or email, and consider blocking or sandboxing untrusted Office documents via attack surface reduction rules or email attachment policies. Note that Protected View can be bypassed by user prompts or misconfiguration, so it is a defense-in-depth measure rather than a complete fix. User awareness training on unsolicited documents remains important given the UI:R precondition.

Affected VersionsENISA

Microsoft Office 365 for Mac 1.0.0 <16.114.26101123
Microsoft Office LTSC 2024 16.0.0 <16.0.17932.21056
Microsoft Office LTSC 2021 16.0.1 <16.0.14334.20974
Microsoft Office LTSC for Mac 2024 16.0.0 <16.114.26101123
Microsoft Office LTSC for Mac 2021 16.0.1 <16.114.26101123
Microsoft 365 Apps for Enterprise 16.0.1 <https://aka.ms/OfficeSecurityReleases

Affected Packages

euvd microsoft_office_365_for_mac fix: 16.114.26101123
euvd microsoft_office_ltsc_2021 fix: 16.0.14334.20974
euvd microsoft_office_ltsc_2024 fix: 16.0.17932.21056
euvd microsoft_office_ltsc_for_mac_2021 fix: 16.114.26101123
euvd microsoft_office_ltsc_for_mac_2024 fix: 16.114.26101123

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 5 packages in euvd

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

Technical ContextAI · show details

The vulnerability is a stack-based buffer overflow (CWE-121) in Microsoft Word's handling of document files. When Word parses a maliciously crafted document, insufficient bounds checking causes data to overwrite the stack, corrupting control-flow data and potentially allowing the attacker to redirect execution to injected code. This class of bug is a well-known vector for remote code execution in document-processing applications because Word runs with the privileges of the opening user and processes untrusted files from email, web downloads, or network shares. CPE strings confirm the affected products include Microsoft 365 Apps for Enterprise, Microsoft Office 365 for Mac, Microsoft Office LTSC 2021/2024, and Microsoft Office LTSC for Mac 2021/2024. The attack is network-reachable (AV:N) and requires user interaction (UI:R) to open the malicious file, but no authentication (PR:N) and low complexity (AC:L) once that interaction occurs.

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Severity by source

Vendor (microsoft) PRIMARY 8.8 HIGH
AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
vuln.today AI 8.8 HIGH

Malicious document is delivered over the network (AV:N) and parsed without privileges (PR:N) but requires the victim to open it (UI:R); memory-corruption RCE yields full C/I/A impact in the user context.

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

Primary rating from Vendor (microsoft).

CVSS VectorVendor: microsoft

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

DescriptionCVE.org

Stack-based buffer overflow in Microsoft Office Word allows an unauthorized attacker to execute code over a network.

Executive ViewAI

Why It Matters

A high-severity remote code execution flaw in Microsoft Word exposes organizations running Microsoft 365 Apps for Enterprise, Office LTSC 2021/2024, and the Mac equivalents, where an attacker can gain code execution on a victim's workstation simply by getting them to open a malicious document. Because Word documents are a routine business communication channel and the attack requires no credentials or special configuration, any employee who opens email or file-share attachments is a potential entry point. Left unaddressed, this represents a credible initial-access path into endpoints that frequently hold access to corporate email, file shares, and connected SaaS applications.

Business Impact: High
Compensating Controls

Apply vendor patch.

Threat Intelligence Overview

EPSS Score
0.4%
Top 63% exploitable
Prevalence
Ubiquitous
Microsoft Office/Word runs on a huge fraction of enterprise and consumer endpoints
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 HIGH
CISA KEV No
Public POC No
EPSS 0.4%
Patch available Yes
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
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
Scheduled
Exploitation
None
System Exposure· derived
Open
Automatable
No
Human Impact
High
Technical Impact
Total

Priority Score

44
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +44
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.

A stack-based buffer overflow occurs when a program writes more data to a buffer located on the stack than it was allocated to hold.

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CVE-2026-55130 HIGH
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CVE-2026-55032 HIGH
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Local code execution in Microsoft Office Word (across Microsoft 365 Apps, Office 2019/LTSC 2021/2024, Office for Mac, an

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