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365 AppsApplication · Microsoft

CVE-2026-40362

HIGH · 7.8 CVSS v3.1 Published 2026-05-12
Fix available
A fix is available. Upgrade to 16.0.10417.20128 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
Use after free 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 use-after-free memory corruption vulnerability in Microsoft Office Excel enables an attacker to achieve code execution locally. The vulnerability stems from improper memory management in Excel's handling of certain objects, where memory is accessed after being freed, potentially allowing an attacker to overwrite function pointers or corrupt memory to gain code execution.

MitigationApply Microsoft security updates for Office Excel as they become available through standard patch management processes. Prioritize patching given the high severity and 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
ExcelApplication
Affected:= 2016
OfficeApplication
Affected:= 2019
Office Long Term Servicing ChannelApplication
Affected:= 2021= 2024
Office Online ServerApplication
Affected:< 16.0.10417.20128

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. Confirm Excel installation
    Open Excel and go to File > Account > About Excel, or run 'winword --version' or 'excel --version' from command line to identify the installed version
    Affected if Excel is not installed, the vulnerability does not apply
  2. Identify Excel version number
    In Excel, click File > Account > About Excel to display the version (e.g., 16.0.xxxxx.xxxxx). For Microsoft 365 Apps, the version will show as a 4-digit release number (e.g., 2406)
    Affected if Version cannot be determined or is not visible in the UI
  3. Compare version to affected ranges
    Match your installed version against: Microsoft 365 Apps (all versions), Excel >= 2016 (16.0.x), Office >= 2019 (16.0.x), Office LTSC >= 2021 or = 2024, Office Online Server < 16.0.10417.20128
    Affected if Your version falls within any of these affected ranges: Microsoft 365 Apps (any), Excel 2016 or later, Office 2019 or later, Office LTSC 2021 or 2024, Office Online Server below 16.0.10417.20128
  4. For Office Online Server environments
    If using Office Online Server, check the version by opening Excel Online or reviewing the server's installed programs list for version 16.0.10417.20128 or lower
    Affected if Office Online Server version is below 16.0.10417.20128

Your environment is affected if any version of Microsoft Excel, Microsoft Office (with Excel component), Microsoft 365 Apps, or Office Online Server matching the affected version ranges is installed and the vulnerable code path is triggered during Excel file processing.

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 16.0.10417.20128 or later
Fixed in 16.0.10417.20128
Interim mitigation

Apply Microsoft security updates for Office Excel as they become available through standard patch management processes. Prioritize patching given the high severity and code execution capability.

Recommended fix Moderate confidence

Install Microsoft Security Updates (CVE-2026-40362); for Office Online Server: version 16.0.10417.20128 or later

  1. Check for and install the latest Microsoft Security Updates for Microsoft Office
  2. Open any Office application (e.g., Excel)
  3. Go to File > Account > Update Options > Update Now
  4. Alternatively, open Windows Settings > Update & Security > Windows Update and check for updates
  5. For Office Online Server, upgrade to version 16.0.10417.20128 or later
Caveat Standard Office update risks—ensure compatibility testing for mission-critical workflows

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
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,224.

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-2026-40362 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