CVE-2025-53739

Code execution via incompatible-type resource access

Published Aug 12, 2025 · Updated Feb 26, 2026

Type confusion in Microsoft Office Excel allows attackers to execute code locally after a user opens a crafted spreadsheet. Microsoft identifies incompatible-type resource access but has not disclosed the parser, object type, or invalid operation that triggers the confusion. User interaction is required, and successful exploitation runs code in the affected Office process.

CVSS severity7.8
High
EPSS probability0.56%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Type confusion in Microsoft Office Excel allows attackers to execute code locally after a user opens a crafted spreadsheet. Microsoft identifies incompatible-type resource access but has not disclosed the parser, object type, or invalid operation that triggers the confusion. User interaction is required, and successful exploitation runs code in the affected Office process.

The record

CVE
CVE-2025-53739
Published
Aug 12, 2025
Updated
Feb 26, 2026
Vendor
Microsoft
Product
Microsoft Office LTSC for Mac 2024
Classifications
CWE-843, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 12, 2025CVE publishedPublication date reported by the CVE source.
  2. Feb 26, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=16.0.0 <16.100.25081015

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Microsoft · Microsoft Office LTSC for Mac 2024version=16.0.0 <16.100.25081015
Microsoft · Microsoft Office 2019version=19.0.0 <https://aka.ms/OfficeSecurityReleases
Microsoft · Microsoft Excel 2016version=16.0.0.0 <16.0.5513.1000
Microsoft · Microsoft Office LTSC for Mac 2021version=16.0.1 <16.100.25081015
Microsoft · Microsoft Office LTSC 2021version=16.0.1 <https://aka.ms/OfficeSecurityReleases
Microsoft · Microsoft Office LTSC 2024version=16.0.0 <https://aka.ms/OfficeSecurityReleases
Microsoft · Office Online Serverversion=16.0.0.0 <16.0.10417.20034
Microsoft · Microsoft 365 Apps for enterpriseversion=16.0.1 <https://aka.ms/OfficeSecurityReleases

Published CVSS scores

7.8Microsoft CorporationCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-843Access of Resource Using Incompatible Type ('Type Confusion')
T1204.002User Execution: Malicious File

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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