CVE-2026-55048
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 · uneditedInteger overflow or wraparound 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 confidenceInteger overflow or wraparound vulnerability in Microsoft Office Excel enables a local attacker to execute arbitrary code by exploiting the memory corruption. A specially crafted Excel file could trigger the overflow, allowing the attacker to gain code execution on the targeted system.
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 'winver' and look for Office/Excel version informationAffected if Excel is present on the system
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Check Excel version numberIn Excel, click File > Account > About Excel, or open Excel and go to File > Account > About [app], or check 'C:\Program Files\Microsoft Office\root\Office16\Excel.exe' version properties, or use 'Get-ItemProperty' PowerShell command on Excel executableAffected if Version matches affected ranges (all versions of Excel 2016 through 2024, Microsoft 365 Apps, Office 2019/2021/2024, or Office Online Server < 16.0.10417.20175)
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Confirm Office version for Microsoft 365/Office AppsOpen any Office app, go to File > Account, look for 'Update Options' and check if updates are enabled, or run 'Get-ItemProperty HKLM:\SOFTWARE\Microsoft\Office\ClickToRun\Configuration -ErrorAction SilentlyContinue | Select-Object ProductReleaseIds,Version'Affected if Office installation exists and updates are not applied (indicating potentially unpatched version)
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Check Office Online Server version if applicableOn server running Office Online Server, run 'Get-OfficeWebAppsEngine' PowerShell cmdlet or check registry: HKLM\SOFTWARE\Microsoft\Office Web Apps\EngineVersions, or check file version of 'sptypes.dll' in the Office Online Server install pathAffected if Office Online Server version is lower than 16.0.10417.20175
User is affected if any version of Excel, Microsoft Office 365 Apps, Office 2016/2019/2021/2024, or Office Online Server below 16.0.10417.20175 is installed and the system handles untrusted Excel 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 Office Excel immediately. Enable Protected View for files from untrusted sources and ensure endpoint protection is active as defense-in-depth.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 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 $5,600.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-55048 — 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-2026-55048 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
- No spam, self-promotion, credentials, or personal data