CVE-2026-55044
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 · uneditedOut-of-bounds read 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 confidenceAn out-of-bounds read vulnerability exists in Microsoft Office Excel that allows an unauthorized attacker to execute code locally. The vulnerability occurs when Excel processes specially crafted files, causing the application to read memory beyond allocated boundaries, which can be leveraged to achieve arbitrary code 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 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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Identify installed Excel versionOpen Excel, go to File > Account > About Excel, or run 'excel /version' from Command Prompt to see the exact version numberAffected if Version falls within the affected range (all versions of Excel 2016, Office 2019/2021/2024, Microsoft 365 Apps, or Office Online Server versions below 16.0.10417.20175) and has not been patched
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Check Microsoft Office versionRun 'winword /version' or 'msiexec /?' from Command Prompt, or view installed programs in Windows Settings to confirm Office installation and versionAffected if Any unpatched installation of Microsoft Office or Microsoft 365 that includes Excel is present
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Verify Excel component versionLocate Excel executable (EXCEL.EXE) in Office installation folder (typically C:\Program Files\Microsoft Office\root\Office## or C:\Program Files (x86)\Microsoft Office\...) and check file properties for version detailsAffected if The Excel executable version matches affected versions and lacks the security patch for this CVE
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Check Office Online Server version (if applicable)If using Office Online Server, run 'Get-OfficeOnlineServerVersion' PowerShell cmdlet or check the product version in Programs and FeaturesAffected if Office Online Server version is below 16.0.10417.20175
If Excel or any Office suite containing Excel is installed and the version has not been updated with the security patch addressing CVE-2026-55044, the environment is vulnerable to out-of-bounds read attacks via specially crafted files.
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 Microsoft security updates for Excel as they become available, and exercise caution when opening files from untrusted sources.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,800.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-55044 — 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-2026-55044 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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