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365 AppsApplication · Microsoft

CVE-2025-53759

HIGH · 7.8 CVSS v3.1 Published 2025-08-12
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
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
Use of uninitialized resource 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

Use of uninitialized resource vulnerability in Microsoft Office Excel that allows an unauthenticated attacker to execute code locally by opening a specially crafted Excel file. The vulnerability stems from improper memory initialization during file parsing, which can be leveraged for code execution.

MitigationApply Microsoft security updates for Office Excel when released; until then, exercise caution with Excel files from untrusted sources and disable macros via Trust Center settings.

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
OfficeApplication
Affected:= 2019
Office Long Term Servicing ChannelApplication
Affected:= 2021= 2024
Office Online ServerApplication
Affected:all versions

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. Check installed Excel version on Windows
    Open Excel, go to File > Account > About Excel, or run 'winword /?' from command prompt to see version info. For Microsoft 365, check File > Account > Update Options to see current channel and version.
    Affected if Version matches Microsoft Office 2019, 2021, 2024, or is an unpatched Microsoft 365 Apps version.
  2. Verify Excel file parsing component
    The vulnerability affects the Excel file parsing engine. Confirm Excel application is present by checking for existence of Excel.exe in typical locations (e.g., C:\Program Files\Microsoft Office\root\Office16 or C:\Program Files (x86)\Microsoft Office\root\Office16).
    Affected if Excel.exe exists and the installed version falls within affected ranges.
  3. Check Office click-to-run version on Windows
    Open Command Prompt and run: 'cd %programfiles%\Microsoft Office\root\Office16' then 'excel.exe /productver' or check registry at HKLM\SOFTWARE\Microsoft\Office\ClickToRun\Configuration for version strings.
    Affected if Version string is empty, missing patches, or matches unpatched 2019/2021/2024/365 versions.
  4. Identify Excel version on Mac
    Open Excel on Mac, go to Excel > About Microsoft Excel to view version number.
    Affected if Version matches affected Office 2019, 2021, 2024 for Mac, or unpatched Microsoft 365 for Mac.
  5. Check Office Online Server version
    On server running Office Online Server, open IIS Manager, select the Office Online site, and check the version of wacserver.exe in the installation directory, or run: Get-ItemProperty 'HKLM:\SOFTWARE\Microsoft\Office Web Apps' | Select-Object ProductVersion.
    Affected if Version is present and represents an unpatched Office Online Server installation.

If Excel or Office Online Server is installed and the installed version falls within the affected ranges (Office 2019, 2021, 2024, or any Microsoft 365 Apps version without the security update), the environment is potentially affected.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply Microsoft security updates for Office Excel when released; until then, exercise caution with Excel files from untrusted sources and disable macros via Trust Center settings.

Recommended fix Moderate confidence

Microsoft 365 Apps (Current Channel or Monthly Enterprise Channel); Office 2024; Office LTSC 2021 with latest security updates; Office Online Server with latest cumulative update

  1. Open Microsoft Excel and go to File > Account > Update Options > Update Now to ensure you have the latest Microsoft 365 updates
  2. For non-subscription Office installations (2019, 2021 LTSC, 2024), run Windows Update or check Microsoft Update Catalog for the latest security updates for Microsoft Office
  3. Verify the installed version includes the security patch for this vulnerability via File > Account > About Excel
  4. Alternatively, uninstall older Office versions and install a newer supported version that includes the fix
  5. For Office Online Server administrators, apply the latest cumulative update from Microsoft Update Catalog
Caveat Standard Office update compatibility; verify add-ins and macros work after updates; LTSC versions require manual patch application

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
  • Implementation1.0 h
  • Testing3.0 h
  • Review / QA2.0 h
8.0 hours of engineering $1,390
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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-2025-53759 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