CVE-2026-55128
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 · uneditedUse after free in Microsoft Office Word 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 confidenceA use-after-free vulnerability in Microsoft Office Word allows an attacker to execute code locally by exploiting improper memory handling. The vulnerability has a CVSS score of 7.8 (HIGH), indicating significant risk for affected systems.
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< 16.0.10417.20175< 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
- 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 Microsoft Word versionOpen Word, go to File > Account > About Word to see the exact version number, or check the registry key HKLM\SOFTWARE\Microsoft\Office\ClickToRun\Configuration or HKLM\SOFTWARE\Microsoft\Office\16.0\Word\InstallRoot for the versionAffected if The version shows 2016 (any build) OR any version of Microsoft 365 Apps, Office 2019, Office 2021, or Office 2024 is installed
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Check Office Online Server versionOpen SharePoint Management Shell and run Get-SPOWebTemplate to identify the server, then check the installed version via Programs and Features or the registry at HKLM\SOFTWARE\Microsoft\Office Server\16.0Affected if Office Online Server version is lower than 16.0.10417.20175
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Identify SharePoint Server versionOpen SharePoint Central Administration > System Settings > Manage farm features, or run Get-SPFarm in SharePoint Management Shell to see the build versionAffected if SharePoint Server 2016 or 2019 is installed, OR the version is lower than 16.0.19725.20434
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Confirm Word is the affected componentVerify the vulnerability exists in the Word component specifically by checking if Word is part of the installed Office suite - open Winword.exe properties or check HKLM\SOFTWARE\Microsoft\Office\ClickToRun\RegistryOverwritesAffected if Word 2016 or any Microsoft 365/Office version with Word component is installed
If Microsoft Word (any version), Microsoft 365 Apps, Office 2019/2021/2024, Office Online Server below 16.0.10417.20175, or SharePoint Server 2016/2019/versions below 16.0.19725.20434 is present, the environment is affected by this use-after-free vulnerability.
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 · scoped16.0.10417.2017516.0.19725.20434
Apply available Microsoft security updates for Office Word promptly, and consider enabling Protected View for documents from untrusted sources to mitigate exploitation.
Microsoft 365/Office 365: Latest version via automatic updates; Office 2016/2019/2021/2024: Latest cumulative security update from Microsoft; Office Online Server: 16.0.10417.20175+; SharePoint Server: 16.0.19725.20434+
- 1. Check for Microsoft Office updates by opening any Office application, going to File > Account, and clicking 'Update Options' > 'Update Now'
- 2. Ensure Windows Update is enabled and run a check for updates via Settings > Update & Security > Windows Update
- 3. For Office Online Server, upgrade to version 16.0.10417.20175 or later
- 4. For SharePoint Server, upgrade to version 16.0.19725.20434 or later
- 5. For Office 2016 Word, apply the specific security update from Microsoft for this CVE
- 6. Verify the update was applied by checking the installed version in File > Account > About Word
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 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 $3,088.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-55128 — 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-2026-55128 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