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365 AppsApplication · Microsoft

CVE-2025-59233

HIGH · 7.8 CVSS v3.1 Published 2025-10-14
Fix available
A fix is available. Upgrade to 16.0.10417.20059 or later.
See remediation →
81/100
Remediation priority · High
No privileges

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Access of resource using incompatible type ('type confusion') in Microsoft Office Excel allows an unauthorized attacker to execute code locally.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

A type confusion vulnerability in Microsoft Office Excel allows an unauthorized local attacker to execute code by exploiting how Excel handles objects of incompatible types. The vulnerability is triggered when a specially crafted Excel file is opened, causing Excel to misuse one object type as another, leading to arbitrary code execution in the current user's context.

MitigationApply Microsoft security updates for Excel as they become available, and enforce least-privilege user permissions to limit the impact of local code execution. Additionally, restrict opening of Excel files from untrusted sources using macro settings and attachment filtering.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
365 AppsApplication
Affected:all versions
ExcelApplication
Affected:= 2016
OfficeApplication
Affected:= 2019
Office Long Term Servicing ChannelApplication
Affected:= 2021= 2024
Office Online ServerApplication
Affected:< 16.0.10417.20059

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
None
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed Excel version
    Open Excel, go to File > Account > About Excel, or check Windows Programs and Features for Microsoft Office/Microsoft Excel version
    Affected if The version falls within affected ranges: Microsoft 365 Apps (all versions), Excel 2016 or later, Office 2019 or later, Office LTSC 2021 or 2024, or Office Online Server version below 16.0.10417.20059
  2. Identify Office Online Server version
    Check server version through Office Online Server administration console or PowerShell Get-OfficeOnlineServerVersion
    Affected if Running Office Online Server with version lower than 16.0.10417.20059
  3. Assess user file opening behavior
    Evaluate whether users in the environment commonly open Excel attachments from email or external/untrusted sources
    Affected if Users routinely open Excel files from untrusted or unknown sources, as the vulnerability is triggered by opening a specially crafted file
  4. Review macro and attachment handling policies
    Check current macro security settings in Excel (File > Options > Trust Center > Trust Center Settings > Macro Settings) and email gateway attachment filtering policies
    Affected if Macro settings permit execution from untrusted sources or attachment filtering is not configured to block suspicious Excel files

A user is affected if they run a vulnerable, unpatched version of Excel/Office (2016 or later, or Microsoft 365) AND open a specially crafted malicious Excel file from an untrusted source.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 16.0.10417.20059 or later
Fixed in 16.0.10417.20059
Interim mitigation

Apply Microsoft security updates for Excel as they become available, and enforce least-privilege user permissions to limit the impact of local code execution. Additionally, restrict opening of Excel files from untrusted sources using macro settings and attachment filtering.

Recommended fix Moderate confidence

Latest patched version via Microsoft Update (Patch Tuesday or latest cumulative update)

  1. Open Microsoft Excel and go to File > Account > Update Options
  2. Select 'Update Now' to download and install the latest Microsoft Office updates
  3. Alternatively, navigate to Microsoft Update Catalog (update.microsoft.com) and search for CVE-2025-59233 security updates
  4. For Office Online Server, upgrade to version 16.0.10417.20059 or later
  5. After updating, restart Excel and verify the version through File > Account > About Excel
Caveat Standard Office update risks apply - ensure compatibility with existing add-ins and macros before deploying enterprise-wide

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in 365 Apps Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,750
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,800.

Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-59233 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data