CVE-2026-55042
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 of uninitialized resource 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 confidenceThis is a memory safety vulnerability in Microsoft Office where an uninitialized variable or memory resource is used, potentially exposing sensitive data from the system's memory to a local attacker. The attacker with local access could exploit this to read information they should not have access to, without requiring elevated privileges.
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 versionsCVSS 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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Identify installed Microsoft Office productsOpen Control Panel > Programs and Features, or run 'Get-ItemProperty HKLM:\Software\Microsoft\Windows\CurrentVersion\Uninstall\* | Select-Object DisplayName, DisplayVersion' in PowerShell to list installed Office productsAffected if Any of the following products are listed: Microsoft 365 Apps, Microsoft 365, Office 2016, Office 2019, Office 2021, or Office 2024
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Verify the installed Office versionOpen any Office application (Word, Excel, etc.), go to File > Account > About [App], or run 'Get-ItemProperty HKLM:\Software\Microsoft\Office\ClickToRun\Configuration | SelectObject VersionToReport' for Microsoft 365/Office 365Affected if Any version is reported, since all versions of the affected products are listed as vulnerable
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Check for installed security updatesOpen Windows Update > View update history, or run 'Get-HotFix | Where-Object {$_.Description -like "*Security*"}' to list installed security updatesAffected if No recent Microsoft Office security updates are installed, or the installed updates predate the patch for CVE-2026-55042 (note: specific patch date may vary by Office version)
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Assess local attack surfaceReview whether the system allows multiple local users, has physical access by untrusted individuals, or runs services that allow local privilege escalationAffected if The system has multiple local users, weak local account controls, or allows physical access by untrusted personnel, enabling a local attacker to trigger the vulnerability
If any affected Microsoft Office product (365 Apps, Office 2016/2019/2021/2024) is installed without the CVE-2026-55042 security update and the system is accessible to a local attacker, the environment is potentially affected.
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 dataApply the appropriate Microsoft security update for the affected Microsoft Office version as soon as it becomes available, and ensure endpoint protection and least-privilege access controls are in place.
- 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-2026-55042 — 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-2026-55042 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