365 AppsApplication · Microsoft

CVE-2026-45645

HIGH · 7.8 CVSS v3.1 Published 2026-06-09
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
Untrusted pointer dereference 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

This is a memory corruption vulnerability in Microsoft Office where the software dereferences a pointer that it does not properly validate or control. An attacker can exploit this to execute arbitrary code locally on the affected system, typically by convincing a user to open a specially crafted Office document.

MitigationApply the latest Microsoft Office security updates immediately. Ensure Microsoft Office is kept current via automatic updates or manual patching. Exercise caution with Office files from untrusted sources and consider enabling Protected View for documents from external sources.

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
Microsoft 365Application
Affected:all versions
Office 2016Application
Affected:all versions
Office 2019Application
Affected:all versions
Office 2021Application
Affected:all versions
Office 2024Application
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. Identify installed Microsoft Office products
    Open Control Panel > Programs and Features, or use command 'Get-ItemProperty HKLM:\Software\Microsoft\Windows\CurrentVersion\Uninstall\* | Select-Object DisplayName, DisplayVersion' in PowerShell to list installed Office applications
    Affected if Any Microsoft Office product from the affected list is present (Microsoft 365 Apps, Microsoft 365, Office 2016, Office 2019, Office 2021, or Office 2024)
  2. Confirm Office version and build number
    Open any Office application (Word, Excel, etc.), go to File > Account, and check the version information under 'About [App]'. Alternatively, run 'winword.exe /?' or 'excel.exe /?' from Command Prompt to display version info
    Affected if The installed version matches any released version of the affected products (all versions are vulnerable)
  3. Verify Office click-to-run installation
    Open Command Prompt and run: 'cd %ProgramFiles%\Microsoft Office\root\Office' then 'dir' to see installed Office structure, or check Program Files for Office executable files
    Affected if Office executables (winword.exe, excel.exe, etc.) are found in standard Office installation directories, indicating an affected installation
  4. Check for pending Office updates
    Open any Office app, go to File > Account > Update Options > Update Now, or check Windows Update history for recent Office security patches
    Affected if No recent security updates have been applied, or the vulnerability remains unpatched regardless of version

If any Microsoft Office product from the affected list (Microsoft 365 Apps, Microsoft 365, Office 2016, 2019, 2021, or 2024) is installed and running, the environment is considered affected since all versions are vulnerable.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the latest Microsoft Office security updates immediately. Ensure Microsoft Office is kept current via automatic updates or manual patching. Exercise caution with Office files from untrusted sources and consider enabling Protected View for documents from external sources.

Fix this in 365 Apps Scoped from the published advisory
  • Consultation4.0 h
  • Implementation4.0 h
  • Testing8.0 h
  • Review / QA4.0 h
20.0 hours of engineering $3,440
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Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2026-45645 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

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-2026-45645 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