CVE-2026-45458
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 allows an unauthorized attacker to execute code locally.
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 enables an unauthenticated attacker to achieve local code execution. The vulnerability involves improper memory management where memory is accessed after being freed, leading to arbitrary code execution in the current process context.
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< 16.0.19725.20384= 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
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/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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Verify Microsoft Office installationCheck for Office applications (winword.exe, excel.exe, etc.) in Program Files\Microsoft Office or Program Files (x86)\Microsoft Office. Use: Get-ChildItem -Path 'C:\Program Files\Microsoft Office', 'C:\Program Files (x86)\Microsoft Office' -Recurse -Filter '*.exe' | Select-Object FullNameAffected if Any Office application executable is found, indicating Microsoft Office is installed (affected since all versions are vulnerable)
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Determine installed Office version via WordOpen Command Prompt and run: winword /? or "C:\Program Files\Microsoft Office\root\OfficeXX\winword.exe" /? where XX is your Office number. The version appears in the dialog or output.Affected if Any version number is returned, confirming Office is installed and potentially affected (affected versions include all versions of Office 2019, 2021, 2024, Microsoft 365 Apps, and Microsoft 365)
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Check Office version via registryQuery registry: Get-ItemProperty -Path 'HKLM:\SOFTWARE\Microsoft\Office\ClickToRun\Configuration' -ErrorAction SilentlyContinue | Select-Object VersionToReport,PlatformAffected if A VersionToReport value is returned, confirming Microsoft 365 Apps is installed and affected (all versions affected)
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Check Microsoft Word version specificallyRun: winword.exe /? or check registry at HKLM\SOFTWARE\Microsoft\Office\16.0\Word\InstallRoot\Path. Also check: Get-ItemProperty 'HKLM:\SOFTWARE\Microsoft\Office\16.0\Common\InstallRoot' -ErrorAction SilentlyContinueAffected if Word version 2016 is found (specifically affected per CVE listing: Microsoft Word = 2016)
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Check SharePoint Server versionQuery registry: Get-ItemProperty -Path 'HKLM:\SOFTWARE\Microsoft\Shared Tools\Web Server Extensions\16.0\WSS\InstalledVersion' -ErrorAction SilentlyContinue. Compare the version string to 16.0.19725.20384Affected if SharePoint 2016, SharePoint 2019, or any version below 16.0.19725.20384 is installed (these specific versions and ranges are affected)
If any Microsoft Office application (including Microsoft 365 Apps, Office 2019/2021/2024) is installed, or if Microsoft Word 2016 or any SharePoint Server version 2016/2019 or below 16.0.19725.20384 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.
From vendor data16.0.19725.20384
Apply Microsoft Office security updates as they become available through standard Microsoft update channels. Prioritize patching for systems handling untrusted documents.
- Consultation3.0 h
- Implementation6.0 h
- Testing4.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-45458 — 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-2026-45458 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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- 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