CVE-2026-55142
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 · uneditedNumeric truncation error in Microsoft Office Word 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 confidenceA numeric truncation error in Microsoft Office Word causes improper handling of numeric values during certain document processing operations. This flaw allows an unauthorized local attacker to potentially access sensitive information that should be protected, due to the way the application truncates numeric data during processing.
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 versionsall versionsall versionsall versionsall versions< 16.0.19725.20434= 2016= 2019= 2016CVSS 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
- None
- Availability
- None
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
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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Check if Microsoft Word 2016 is installedOpen Word, go to File > Account > About Word, or run 'winword /?' from command prompt, or check Add/Remove ProgramsAffected if Version shows 16.0.xxxx and matches the build number in the affected version range
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Identify SharePoint Server versionCheck SharePoint Central Administration > System Settings > Manage farm servers, or run Get-SPFarm in SharePoint Management ShellAffected if Version is 2016 or 2019, or build is below 16.0.19725.20434
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Verify Microsoft 365 subscription statusCheck Office Account settings in any Office app, or view subscription info at admin.microsoft.comAffected if Subscription is active and Office apps are installed (all versions affected per CVE)
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Confirm local document processing usageReview whether users process untrusted or externally-sourced Word documents locallyAffected if Users open Word documents from untrusted sources (vulnerability triggers during document processing)
Environment is affected if Microsoft Word 2016 is installed, or SharePoint Server 2016/2019 with build below 16.0.19725.20434 is used, or Microsoft 365/Office apps with active subscription are deployed, and users process documents that could trigger the numeric truncation flaw.
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 · scoped16.0.19725.20434
Apply available Microsoft security updates for Office Word as they become released; ensure regular patch management and system updates are implemented organization-wide.
Microsoft 365/Office 365: Latest version via subscription updates; Office 2024: Install latest updates or upgrade to Office 2024 LTSC; Office 2021/2019: Apply latest C2R or MSI security updates; SharePoint Server: Upgrade to version 16.0.19725.20434 or later; Word 2016: Apply security update KB50557
- Open Microsoft Word and go to File > Account > Update Options > Update Now to receive the latest security patches
- Alternatively, navigate to Microsoft Update at update.microsoft.com and install all pending security updates for Microsoft Office
- For enterprise deployments, use Microsoft Endpoint Configuration Manager or Windows Server Update Services (WSUS) to deploy security update KBxxxxxx (check MSRC for specific KB number)
- After updating, verify the installed version includes the security fix by checking File > Account > About Word
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation4.0 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 $2,560.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-55142 — 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-2026-55142 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