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365 AppsApplication · Microsoft

CVE-2026-55141

HIGH · 7.8 CVSS v3.1 Published 2026-07-14
Fix available
A fix is available. Upgrade to 16.0.10417.20175 or later.
See remediation →
81/100
Remediation priority · High
No privileges 5 weeks old

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
Stack-based buffer overflow in Microsoft Office Excel allows an unauthorized attacker to execute code locally.

In the news

Third-party coverage
Trending covered by 1 outlet this week · latest 1mo ago

Surfaced from public web coverage — external links open in a new tab.

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

Stack-based buffer overflow in Microsoft Office Excel that allows an unauthorized attacker to execute code locally via malformed Excel files.

MitigationApply Microsoft security patches for Excel; until patched, avoid opening untrusted Excel files and consider disabling macro execution.

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
Microsoft 365Application
Affected:all versions
Office 2019Application
Affected:all versions
Office 2021Application
Affected:all versions
Office 2024Application
Affected:all versions
Office Online ServerApplication
Affected:< 16.0.10417.20175

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 Microsoft Excel is installed
    Open Windows Terminal or Command Prompt and run: excel /? or winword /? (if Excel is part of Office suite). Alternatively, check Add/Remove Programs or the Start Menu for Microsoft Excel.
    Affected if Excel is not installed on the system, the vulnerability does not apply.
  2. Determine installed Excel version
    Open Excel, go to File > Account > About Excel. Or in Command Prompt run: excel /x and check the version dialog. For Office Click-to-Run, run: powershell "(Get-ItemProperty HKLM:\SOFTWARE\Microsoft\Office\ClickToRun\Configuration).ProductReleaseIds"
    Affected if The installed version falls within the affected ranges: any version of Microsoft 365 Apps, Office 2019, Office 2021, Office 2024, or Office Online Server version lower than 16.0.10417.20175.
  3. Check Office Online Server version (if applicable)
    If using Office Online Server, run: Get-OfficeOnlineServerVersion or check the registry under HKLM\SOFTWARE\Microsoft\OfficeServer\16.0 for the version value.
    Affected if The Office Online Server version is lower than 16.0.10417.20175.
  4. Identify Excel file handling as attack surface
    Verify that Excel is configured to open files (default state). Check if Excel is set as the default handler for .xlsx/.xls files by viewing File Associations in Windows Settings > Apps > Default Apps.
    Affected if Excel can open files. The vulnerability triggers when opening a malformed Excel file, so any configuration allowing file opening represents the exploitable condition.

The environment is affected if Microsoft Excel is installed and the installed version matches any of the affected versions (Microsoft 365 Apps, Office 2019/2021/2024 all versions, or Office Online Server below 16.0.10417.20175).

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 16.0.10417.20175 or later
Fixed in 16.0.10417.20175
Interim mitigation

Apply Microsoft security patches for Excel; until patched, avoid opening untrusted Excel files and consider disabling macro execution.

Recommended fix Moderate confidence

Microsoft Office security updates (specific version varies by product; check Microsoft Update Catalog for CVE-2026-55141)

  1. 1. Check for Microsoft Office updates via File > Account > Update Options > Update Now in any Office application
  2. 2. Alternatively, visit https://portal.office.com/account/ and install all available Office updates
  3. 3. For enterprise deployments, use Microsoft Update Catalog or WSUS to deploy the latest Office security patches
  4. 4. Verify the update was installed successfully by checking Office version information
  5. 5. For Office Online Server specifically, upgrade to version 16.0.10417.20175 or later
Caveat Standard Office updates typically have minimal breaking changes; verify compatibility with your organization's line-of-business add-ins

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
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
Get the upgrade done

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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-2026-55141 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