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365 AppsApplication · Microsoft

CVE-2026-26110

HIGH · 7.8 CVSS v3.1 Published 2026-03-10
Fix available
A fix is available. Upgrade to 16.0.19822.20000 or later.
See remediation →
80/100
Remediation priority · High
Zero-click

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
Access of resource using incompatible type ('type confusion') 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 type confusion vulnerability in Microsoft Office where the software incorrectly handles resources using incompatible types, allowing an unauthorized attacker to execute code locally on the affected system. Type confusion occurs when the program uses one data type when another is expected, leading to memory corruption and potential code execution.

MitigationApply Microsoft security updates for Microsoft Office as they become available through Windows Update or manual download from Microsoft Update Catalog. Verify that Microsoft Office is fully patched to the latest version.

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
365 CopilotApplication
Affected:< 16.0.19822.20000
OfficeApplication
Affected:= 2016= 2019
Office Long Term Servicing ChannelApplication
Affected:= 2021= 2024

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
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/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 product
    Open any Office application (Word, Excel, PowerPoint). Go to File > Account. Note the product name (e.g., Microsoft 365, Microsoft Office LTSC, Microsoft 365 Copilot).
    Affected if Product is Microsoft 365 Apps, Microsoft 365 Copilot, Office 2016, Office 2019, Office LTSC 2021, or Office LTSC 2024.
  2. Get Office application version
    In any Office app, go to File > Account > About [App]. Record the version number displayed (e.g., 16.0.14332.20463). Alternatively, open Excel, go to File > Account, and check the version shown under "About Microsoft [App]."
    Affected if A version number is displayed indicating any Microsoft Office installation.
  3. Check Microsoft 365 Apps version
    If product is Microsoft 365 Apps (or shows "Microsoft 365 for enterprise"), compare the version to the most recent patch. Open Word/Excel > File > Account > Check for Updates to see current installed version. The 'all versions' note means any unpatched version is affected.
    Affected if Microsoft 365 Apps is installed and has not been patched to a version that addresses CVE-2026-26110.
  4. Check Microsoft 365 Copilot version
    If Copilot is installed, open Word or Excel and check the Copilot version via the Copilot pane or go to File > Account > About Microsoft [App]. Note the version number (e.g., 16.0.19822.20000).
    Affected if Copilot version is less than 16.0.19822.20000.
  5. Check Office 2016 or 2019 version
    Open File > Account > About [Word/Excel]. The version will be 16.0.xxxx.xxxx format. For Office 2016, versions typically start with 16.0.4xxx; for Office 2019, typically 16.0.10xxx or higher. The CVE lists exact version matches.
    Affected if Office 2016 (exact version per CVE) or Office 2019 (exact version per CVE) is installed.
  6. Check Office LTSC 2021 or 2024 version
    Open File > Account > About [App]. Office LTSC 2021 version format is typically 16.0.14xxx.xxxx; Office LTSC 2024 is 16.0.19xxx.xxxx or higher. The CVE lists exact version matches for these LTSC releases.
    Affected if Office LTSC 2021 (exact version per CVE) or Office LTSC 2024 (exact version per CVE) is installed.

If any Microsoft 365 Apps, Copilot version below 16.0.19822.20000, Office 2016, Office 2019, Office LTSC 2021, or Office LTSC 2024 matching the exact affected versions is installed without the CVE-2026-26110 security patch, the environment is 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.

From vendor data
Upgrade available Upgrade to 16.0.19822.20000 or later
Fixed in 16.0.19822.20000
Interim mitigation

Apply Microsoft security updates for Microsoft Office as they become available through Windows Update or manual download from Microsoft Update Catalog. Verify that Microsoft Office is fully patched to the latest version.

Fix this in 365 Apps Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing4.0 h
  • Review / QA2.0 h
15.0 hours of engineering $2,640
Get the upgrade done

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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-2026-26110 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