CVE-2026-55028
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 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 confidenceAn out-of-bounds read vulnerability in Microsoft Office allows a local attacker to read sensitive information from memory due to improper bounds checking during file processing operations.
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 versionsall versions< 16.0.19725.20434= 2016= 2019CVSS 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.
-
Check installed Office version on WindowsOpen Command Prompt or PowerShell and run: reg query 'HKLM\SOFTWARE\Microsoft\Office\ClickToRun\Configuration' /v Version 2>nul || reg query 'HKLM\SOFTWARE\Microsoft\Office\16.0\Common\InstallRoot' /v Version 2>nul || reg query 'HKLM\SOFTWARE\Microsoft\Office\19.0\Common\InstallRoot' /v Version 2>nulAffected if Any version is returned - the CVE states all versions of Office 2016, 2019, 2021, and 2024 are affected when unpatched
-
Check Microsoft 365 Apps installationOpen PowerShell and run: Get-ItemProperty 'HKLM:\SOFTWARE\Microsoft\Office\ClickToRun\Configuration' | Select-Object -Property Platform, Version, ProductReleaseIdsAffected if Any Microsoft 365 Apps are installed - the CVE states all versions of Microsoft 365 Apps are affected when unpatched
-
Check Microsoft 365 subscription statusOpen PowerShell and run: Get-AppxPackage -Name 'Microsoft.Office.Desktop' | Select-Object Name, VersionAffected if Microsoft Office desktop app is installed via Microsoft 365 subscription - the CVE states all Microsoft 365 versions are affected when unpatched
-
Check SharePoint Server versionOpen SharePoint Management Shell and run: (Get-SPFarm).BuildVersion.ToString() OR check Program Files\Common Files\Microsoft Shared\Web Server Extensions\16\BIN\setup.exe versionAffected if Version is less than 16.0.19725.20434, or the product is SharePoint Server 2016 or SharePoint Server 2019 (any build)
-
Identify vulnerable Office componentsOpen Control Panel > Programs and Features, look for Microsoft Office entries including Word, Excel, PowerPoint, Outlook, or check via PowerShell: Get-ItemProperty 'HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\*' | Where-Object {$_.DisplayName -like '*Office*'} | Select-Object DisplayName, DisplayVersionAffected if Any Microsoft Office application is listed as installed without confirmed security update for this CVE
If any Microsoft Office product (Office 2016/2019/2021/2024, Microsoft 365 Apps, or SharePoint Server 2016/2019 below build 16.0.19725.20434) is installed and unpatched, the environment is affected by this out-of-bounds read 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.
From vendor data16.0.19725.20434
Apply Microsoft security updates for affected Office versions once available. Until patch release, limit local access to systems running Office and monitor for indicators of exploitation.
- Consultation2.0 h
- Implementation3.0 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 $2,272.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-55028 — 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-2026-55028 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
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
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