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365 AppsApplication · Microsoft

CVE-2025-59231

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 specially crafted malicious Excel files to trigger improper type handling, enabling an attacker to execute arbitrary code locally on the affected system.

MitigationApply Microsoft security updates for Office Excel as they become available through standard patch management processes, and enable Protected View for files from untrusted sources to reduce exploitation risk.

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 Microsoft Excel version
    Open Excel, go to File > Account > About Excel. Alternatively, open Command Prompt and run: winofficever.exe or check Programs and Features for Microsoft Office installation.
    Affected if Version is 2016 or later, or version is 2019 or later, or version is 2021/2024 LTSC, or product is Microsoft 365 Apps (any version).
  2. Determine exact Office build number for Microsoft 365/Office 2021+
    In Excel, go to File > Account > About Excel and note the full version string (e.g., 16.0.xxxxx.xxxxx). For Microsoft 365, also check Office Account > Update Options to see update channel.
    Affected if Build number is 16.0.xxxxx.xxxxx (any Microsoft 365 build) and falls below fixed version.
  3. Check Microsoft Office Online Server version
    On the server running Office Online Server, open SharePoint Management Shell and run: Get-OfficeWebAppsServer | Select-Object BuildVersion. Or check installed programs for Office Online Server version.
    Affected if Build version is lower than 16.0.10417.20059.
  4. Verify if Excel is used to open files from untrusted sources
    Check Excel Trust Center settings: File > Options > Trust Center > Trust Center Settings > Protected View. Observe whether files from Internet, Outlook, or potentially unsafe locations are opened in Protected View.
    Affected if Protected View is disabled for any of the three source options, increasing exposure to malicious files.

You are affected if you run any version of Microsoft Excel 2016 or later, Microsoft Office 2019 or later, Microsoft 365 Apps, Office LTSC 2021/2024, or Office Online Server versions below 16.0.10417.20059, and open untrusted Excel files with Protected View disabled.

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 Office Excel as they become available through standard patch management processes, and enable Protected View for files from untrusted sources to reduce exploitation risk.

Recommended fix Moderate confidence

Office Online Server: 16.0.10417.20059 or later; Other products: latest patched version via Microsoft Update

  1. For Office 365 Apps: Ensure automatic updates are enabled or manually check for updates via File > Account > Update Options > Update Now
  2. For Office Online Server: Upgrade to version 16.0.10417.20059 or later by installing the latest cumulative update from the Microsoft Update Catalog or using Windows Update
  3. For Excel 2016, Office 2019, Office LTSC 2021, and Office LTSC 2024: Apply the latest Microsoft security updates via Windows Update or download updates from the Microsoft Update Catalog
Caveat Standard Office update apply without expected breaking changes for this security patch

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

Fix this in 365 Apps Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,130
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,408.

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-2025-59231 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