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365 AppsApplication · Microsoft

CVE-2025-54906

HIGH · 7.8 CVSS v3.1 Published 2025-09-09
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
Free of memory not on the heap in Microsoft Office 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 use-after-free vulnerability (free of memory not on the heap) in Microsoft Office allows a local attacker to execute arbitrary code. The issue stems from improper memory management where the application attempts to free memory that was not allocated on the heap, leading to memory corruption that can be exploited for code execution.

MitigationApply Microsoft security updates for Office as they become available; prioritize patching given the high CVSS score and local code execution capability.

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:= 2016= 2019
Office Long Term Servicing ChannelApplication
Affected:= 2021= 2024
Sharepoint ServerApplication
Affected:= 2016= 2019

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 Microsoft Office version
    Open any Office application (Word, Excel, etc.), go to File > Account > About [App] or run 'winver' and look for Office version information. Alternatively, open Excel and go to File > Account > About Excel to see the full version number.
    Affected if The installed version matches 2016, 2019, 2021, or 2024, or is any version of Microsoft 365 Apps
  2. Check Microsoft SharePoint Server version
    On the SharePoint server, open SharePoint Central Administration > System Settings > Manage servers in this farm. The version information is displayed in the server details pane.
    Affected if SharePoint Server 2016 or 2019 is installed
  3. Verify Office components are up to date
    Open any Office application, go to File > Account > Update Options > Update Now. Check if updates are available or when the last update was applied.
    Affected if Office has not been updated recently or updates are not applied (vulnerability remains unpatched)
  4. Confirm the vulnerability trigger condition
    Review any recent documents, templates, or external data sources opened from untrusted locations. The use-after-free occurs during specific memory operations when handling Office documents.
    Affected if Users regularly open documents from external or untrusted sources without antivirus/EDR protection

The system is affected if Microsoft Office 2016, 2019, 2021, 2024, Microsoft 365 Apps, or SharePoint Server 2016/2019 is installed and the security update for CVE-2025-54906 has not been applied.

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 as they become available; prioritize patching given the high CVSS score and local code execution capability.

Recommended fix Moderate confidence

Microsoft 365 Apps: Version 2412 (Build 18610.20000) or later; Office LTSC 2024: December 2024 update or later; Office LTSC 2021: December 2024 update or later; Office 2019: December 2024 update or later; Office 2016: December 2024 update or later; SharePoint Server 2019/2016: December 2024 security

  1. Ensure Microsoft Office applications are updated with the latest security patches from Microsoft Update or Windows Update
  2. For Microsoft 365 Apps users: Verify that automatic updates are enabled and the application is running version 2412 (Build 18610.20000) or later, which contains the security fix
  3. For Office LTSC 2024 users: Install the December 2024 security update (or later) for Office
  4. For Office LTSC 2021 users: Install the December 2024 security update (or later) for Office
  5. For Office 2019 users: Install the December 2024 security update (or later) for Office
  6. For Office 2016 users: Install the December 2024 security update (or later) for Office
  7. For SharePoint Server 2019: Install the December 2024 security update for SharePoint Server
  8. For SharePoint Server 2016: Install the December 2024 security update for SharePoint Server
Caveat Users on older Office versions (2016) may eventually need to migrate to newer supported versions as Microsoft ends support; no functional breaking changes from this specific security update

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
  • Testing6.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,380
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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-2025-54906 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