CVE-2026-55025
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 · uneditedAccess of resource using incompatible type ('type confusion') in Microsoft Office Excel allows an unauthorized attacker to execute code locally.
In the news
Third-party coverage- Microsoft July 2026 Patch Tuesday fixes massive 570 flaws, 3 zero-days
- Microsoft CVE Summary - Bleeping Computer
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 confidenceA type confusion vulnerability in Microsoft Office Excel allows an attacker to execute arbitrary code locally by exploiting how the application handles resources with incompatible types. This memory corruption issue can be triggered through a specially crafted Excel file, potentially giving the attacker the same privileges as the local user.
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 dataall versions= 2016all versionsall versionsall versionsall versions< 16.0.10417.20175CVSS 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 checksWork through these to decide whether this CVE applies to you.
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Verify Excel is installedOpen Excel, go to File > Account > About Excel, or run 'winword --version' or check Programs and Features for Microsoft ExcelAffected if Excel is not installed, the vulnerability does not apply
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Determine installed Excel versionIn Excel: File > Account > About Excel. On Windows: open Excel, press Alt+F11 for VBA, ?-Version in immediate window, or check registry HKLM\SOFTWARE\Microsoft\Office\ClickToRun\Configuration or HKLM\SOFTWARE\Microsoft\Office\16.0\Excel\InstallRootAffected if Version falls within affected ranges (Excel 2016+, Office 2019/2021/2024, Microsoft 365 Apps, or Office Online Server < 16.0.10417.20175)
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Confirm file handling capabilityVerify Excel can open and process .xlsx files - the vulnerability is triggered when opening a specially crafted Excel file, so ensure the application is functional and not in a blocked/disabled stateAffected if Excel is fully functional and can open files, meaning the attack surface exists
If Microsoft Excel is installed and running any version from 2016 onward, or any Microsoft 365/Office 2019/2021/2024 version, or Office Online Server versions below 16.0.10417.20175, the environment is affected by this vulnerability.
Generated from the published advisory. Verify against your own configuration.
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 data16.0.10417.20175
Apply the appropriate Microsoft security update for the affected Excel versions as soon as practical, and restrict opening of untrusted Excel files from unknown sources until the patch is deployed.
- Consultation2.0 h
- Implementation3.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,040.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-55025 — 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 sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-55025 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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
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