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Vulnerability Assessment

Weakness
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Heap 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.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
Patch available 0.3% exploitation probability (EPSS)

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AnalysisAIv1 – Jul 14, 2026

Local code execution in Microsoft Office (Microsoft 365 Apps, Office 2016/2019, LTSC 2021/2024, and Office for Mac) arises from a heap-based buffer overflow (CWE-122) that an attacker triggers by convincing a user to open a maliciously crafted document. The CVSS 3.1 score is 7.8 (AV:L/AC:L/PR:N/UI:R) with high impact to confidentiality, integrity, and availability, meaning code runs in the context of the current user. No public exploit identified at time of analysis, and it is not listed in CISA KEV; a vendor patch is available via MSRC.

Affected VersionsENISA

Microsoft Office LTSC for Mac 2024 16.0.0 <16.111.26071215
Microsoft Office LTSC 2024 16.0.0 <https://aka.ms/OfficeSecurityReleases
Microsoft Office LTSC for Mac 2021 16.0.1 <16.111.26071215
Microsoft 365 Apps for Enterprise 16.0.1 <https://aka.ms/OfficeSecurityReleases
Microsoft Office 2019 19.0.0 <https://aka.ms/OfficeSecurityReleases
Microsoft Office 2016 16.0.0 <16.0.5561.1000
Microsoft Office 365 for Mac 1.0.0 <16.111.26071215
Microsoft Office LTSC 2021 16.0.1 <https://aka.ms/OfficeSecurityReleases

Affected Packages

euvd microsoft_office_2016 fix: 16.0.5561.1000
euvd microsoft_office_365_for_mac fix: 16.111.26071215
euvd microsoft_office_ltsc_for_mac_2021 fix: 16.111.26071215
euvd microsoft_office_ltsc_for_mac_2024 fix: 16.111.26071215

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 4 packages in euvd

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

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (microsoft) PRIMARY 7.8 HIGH
AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Primary rating from Vendor (microsoft) · only source for this CVE.

CVSS VectorVendor: microsoft

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

DescriptionCVE.org

Heap-based buffer overflow in Microsoft Office allows an unauthorized attacker to execute code locally.

Executive ViewAI

Why It Matters

A heap-based buffer overflow in Microsoft Office (365 Apps, 2016, 2019, LTSC 2021/2024, and macOS versions) enables local code execution when users open maliciously crafted documents, potentially compromising system integrity and data confidentiality within user privileges. While no public exploit has been identified at the time of analysis, the vulnerability's ease of exploitation and broad user base warrant rapid patching to prevent social engineering attacks.

Recommended Action

Within 24 hours, inventory Office deployments across the organization (Microsoft 365 Apps, Office 2016, Office 2019, Office LTSC 2021, Office LTSC 2024, and Office for Mac) and issue a security advisory warning users against opening unexpected or suspicious Office documents from untrusted sources. Within 7 days, obtain the latest security patches from Microsoft Security Response Center (MSRC) for each affected version and conduct testing in a non-production environment to validate compatibility with critical business workflows. Within 30 days, complete deployment of patches across all affected Office installations and confirm patch status through WSUS or Microsoft Update logs, prioritizing business-critical systems and departments in the first week.

Business Impact: High
Compensating Controls

Apply vendor patch.

Threat Intelligence Overview

EPSS Score
0.3%
Top 73% exploitable
Threat Intel
1
1 sources
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 0.3%
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
Small
Automatable
No
Human Impact
High
Technical Impact
Total

Priority Score

39
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +39
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 heap overflow occurs when a program writes data beyond the bounds of a buffer allocated in the heap memory region.

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