CVE-2026-55037
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 · uneditedHeap-based buffer overflow 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 confidenceHeap-based buffer overflow vulnerability in Microsoft Office Excel allows an attacker to execute code locally by overflowing heap memory when processing specially crafted Excel files.
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 'winword /?' from command prompt to see Office version. Alternatively, check registry key HKLM\SOFTWARE\Microsoft\Office\ClickToRun\Configuration for Microsoft 365/Office apps.Affected if Version matches an affected product (Excel 2016+, Office 2019/2021/2024, Microsoft 365 Apps, or Office Online Server below 16.0.10417.20175)
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Confirm Office variantVerify whether the installation is Microsoft 365 Apps, Office 2019, Office 2021, Office 2024, or Office Online Server using Programs and Features or the Office portal admin center.Affected if Any of these Office variants are present without the specific security patch
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Check Office Online Server versionFor Office Online Server specifically, run Get-OfficeWebAppsServer or check the installed version number in Programs and Features.Affected if Version is lower than 16.0.10417.20175
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Determine patch statusOpen Excel, go to File > Account > Update Options and check if updates are installed. Alternatively, check Windows Update history for recent Office security updates.Affected if No recent Office/Excel security updates have been applied to an affected version
If Microsoft Excel or any affected Office product is installed and has not received the specific security patch for this CVE, opening a specially crafted Excel file could trigger the heap-based buffer overflow and allow remote code execution.
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.
dbcve · scoped16.0.10417.20175
Apply Microsoft security updates for Office Excel immediately; until patched, avoid opening untrusted Excel files from unknown sources.
Microsoft security update for CVE-2026-55037 (check MSRC for specific KB article number for your Office version)
- Check for Microsoft Office updates via File > Account > Update Options > Update Now in any Office application
- Alternatively, navigate to Microsoft Update at https://update.microsoft.com/ and install all pending security updates
- Verify the Excel version after update: File > Account > About Excel to confirm the installed version includes the security patch
- For Office Online Server, upgrade to version 16.0.10417.20175 or later
- If automatic updates are disabled, manually download the specific security patch from the Microsoft Catalog at https://catalog.update.microsoft.com/
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation1.0 h
- Testing2.0 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 $1,696.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-55037 — 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-2026-55037 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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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.
- 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