CVE-2026-54988
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 disclose information 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 confidenceOut-of-bounds read vulnerability in Microsoft Office Excel that allows a local unauthorized attacker to read sensitive information from memory beyond intended boundaries, leading to information disclosure.
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
- Low
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/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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Confirm Excel installationOpen Excel and go to File > Account > About Excel, or run 'winword --version' or 'excel --version' from command line to check if Microsoft Excel is present on the systemAffected if Excel is installed and running any version of Microsoft 365 Apps, Excel 2016, Office 2019, Office 2021, Office 2024, or Office Online Server below build 16.0.10417.20175
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Identify installed Excel versionIn Excel, go to File > Account > About Excel to view the version number, or open Command Prompt and run 'cscript "C:\Program Files\Microsoft Office\root\Office16\OSPP.VBS" /dstatus' to query Office licensing informationAffected if The displayed version matches any of the affected products listed (Microsoft 365 Apps, Excel 2016, Office 2019, Office 2021, or Office 2024) and has not received the specific security patch for this CVE
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Check Office Online Server build versionIf using Office Online Server, run 'Get-OfficeWebAppsVersion' in PowerShell on the server, or check the build number in the Office Online Server administration console under Server > AboutAffected if The build version is lower than 16.0.10417.20175
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Verify patch statusOpen Windows Update > View update history, or check Microsoft Update Catalog for installed security updates related to Excel/CVE-2026-54988, or run 'Get-HotFix | Where-Object {$_.Description -like "Security Update"}' in PowerShellAffected if No security update specifically addressing CVE-2026-54988 for Excel has been installed on the system
A user is affected if Microsoft Excel is installed and running any version of Microsoft 365 Apps, Excel 2016, Office 2019/2021/2024, or Office Online Server below build 16.0.10417.20175, and the corresponding security patch for CVE-2026-54988 has not been applied.
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 when available; exercise caution with Excel files from untrusted or unknown sources to reduce exposure.
- Consultation2.0 h
- Implementation2.0 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 $1,984.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-54988 — 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-2026-54988 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