dbcve.org
365 AppsApplication · Microsoft

CVE-2026-26108

HIGH · 7.8 CVSS v3.1 Published 2026-03-10
Fix available
A fix is available. Upgrade to 16.0.10417.20102 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
Heap-based buffer overflow 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 heap-based buffer overflow vulnerability exists in Microsoft Office Excel that allows an unauthorized attacker to execute arbitrary code locally on the affected system. The vulnerability stems from improper memory handling when Excel processes specially crafted files, leading to heap memory corruption that can be exploited to achieve code execution.

MitigationApply the latest Microsoft security updates for Microsoft Office Excel as soon as they become available. Until the patch is deployed, exercise caution with Excel files from untrusted sources and consider enabling protected view settings in Office.

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:< 16.0.10417.20102all 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. Confirm Microsoft Excel is installed
    Open Excel and go to File > Account > About Excel, or check Program Files\Microsoft Office\ for Excel.exe, or run 'Get-ItemProperty HKLM:\Software\Microsoft\Windows\CurrentVersion\App*\Excel' in PowerShell
    Affected if Excel is not installed on the system
  2. Determine installed Excel version number
    In Excel, click File > Account > About Excel and note the version number (e.g., 16.0.xxxxx.xxxxx), or run 'Get-ItemProperty "HKLM:\SOFTWARE\Microsoft\Office\ClickToRun\Configuration" | Select-Object VersionToReport' in PowerShell
    Affected if Unable to determine the version number
  3. Check if running Microsoft 365 Apps
    Open Excel, go to File > Account. Look for 'Microsoft 365' under subscription information. Alternatively, check registry key HKLM\SOFTWARE\Microsoft\Office\ClickToRun\Configuration for ProductReleaseIds containing 'Excel'
    Affected if Running Microsoft 365 Apps (all versions are affected)
  4. Compare Excel 2016/2019/LTSC 2021/LTSC 2024 versions
    If running standalone Office (not Microsoft 365), check the exact version from Step 2. For Excel 2016, 2019, LTSC 2021, or LTSC 2024, all versions within those release lines are affected based on the CVE scope
    Affected if Running Excel 2016, 2019, LTSC 2021, or LTSC 2024 (all versions in those releases)
  5. Check Microsoft Office Online Server version (if applicable)
    If hosting Office Online Server, run 'Get-OfficeWebAppsMachine' cmdlet or check the installed version against 16.0.10417.20102
    Affected if Office Online Server version is below 16.0.10417.20102 or is an affected release version

If Microsoft Excel (any variant) is installed and the version falls within the affected ranges (Microsoft 365 Apps all versions, Excel 2016/2019/LTSC 2021/LTSC 2024 all versions, or Office Online Server below 16.0.10417.20102), the system is potentially affected by this vulnerability when opening untrusted Excel files.

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 16.0.10417.20102 or later
Fixed in 16.0.10417.20102
Interim mitigation

Apply the latest Microsoft security updates for Microsoft Office Excel as soon as they become available. Until the patch is deployed, exercise caution with Excel files from untrusted sources and consider enabling protected view settings in Office.

Fix this in 365 Apps Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,130
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,408.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2026-26108 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2026-26108 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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