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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.

Act Now Prioritize within 24-48h. Why: Active threat signals + CRITICAL/HIGH severity.
Patch available 0.3% exploitation probability (EPSS)

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AnalysisAIv1 – Jul 14, 2026

Local code execution in Microsoft Office PowerPoint (including Microsoft 365 Apps, Office 2019, Office LTSC 2021/2024, and their macOS variants) arises from a heap-based buffer overflow triggered when a victim opens a maliciously crafted presentation file. Successful exploitation runs attacker-controlled code with the privileges of the current user, yielding full confidentiality, integrity, and availability impact. There is no public exploit identified at time of analysis and the issue is not listed in CISA KEV, but Microsoft has released a patch.

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 2019 19.0.0 <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 PowerPoint 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_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
euvd microsoft_powerpoint_2016 fix: 16.0.5561.1000

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
ENISA EUVD CRITICAL

Primary rating from Vendor (microsoft).

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 PowerPoint allows an unauthorized attacker to execute code locally.

Executive ViewAI

Why It Matters

A local code execution vulnerability in Microsoft Office PowerPoint (CVE-2026-55123, CVSS 7.8) enables attackers to compromise users' systems through maliciously crafted presentation files. This affects Microsoft 365 Apps, Office 2019, and Office LTSC 2021/2024 across Windows and macOS, exposing any organization that exchanges presentations to potential data breach or system compromise. The vulnerability requires a vendor patch to remediate and should be prioritized for rapid deployment.

Recommended Action

Within 24 hours, inventory all systems running affected Microsoft Office versions (Microsoft 365 Apps, Office 2019, Office LTSC 2021/2024) and communicate risks to users, advising against opening presentations from untrusted sources until patching is complete. Within 7 days, deploy the vendor-released patch across the organization, prioritizing systems with highest exposure to external presentations and communications. Within 30 days, complete patching of all affected systems and validate through automated compliance reporting to confirm remediation.

Business Impact: High
Compensating Controls

Apply vendor patch.

Threat Intelligence Overview

EPSS Score
0.3%
Top 73% exploitable
EU Gov Alert
Listed
Top-tier national CERT alert
Threat Intel
2
1 sources
Vendor Status
Publicly Disclosed:No
Exploited:No
Latest Software Release:Exploitation Less Likely
Data Quality
6 sources
Confidence: High

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 Yes
Deciding rule
Active threat signals + CRITICAL/HIGH severity
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

59
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +39
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: +20

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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