CVE-2025-30376
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 · uneditedHeap-based buffer overflow in Microsoft Office Excel 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 confidenceThis is a heap-based buffer overflow vulnerability in Microsoft Office Excel that allows an unauthorized local attacker to execute arbitrary code. The vulnerability stems from improper memory handling when Excel processes specially crafted files, leading to heap memory corruption that can be exploited to gain code execution 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 versions= 2016= 2019= 2021= 2024< 16.0.10417.20010CVSS 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.
-
Verify Microsoft Excel is installedCheck for Excel executable at typical installation paths such as C:\Program Files\Microsoft Office\root\Office16\EXCEL.EXE or C:\Program Files (x86)\Microsoft Office\root\Office16\EXCEL.EXE. Alternatively, query the Windows Registry under HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\EXCEL.EXEAffected if Excel executable is not found on the system, the system is not affected by this vulnerability.
-
Determine installed Excel versionOpen Excel, go to File > Account > About Excel. Alternatively, right-click EXCEL.EXE in the installation directory, select Properties, and view the Details tab for the Product Version.Affected if The installed version falls within these ranges: Microsoft 365 Apps (any version until patched), Excel 2016 and later, Office 2019 and later, Office LTSC 2021 or 2024, or Office Online Server versions earlier than 16.0.10417.20010.
-
Check Microsoft Office version via registryQuery HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office\ClickToRun\Configuration or HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office\16.0\Common\InstallRoot for the ProductReleaseIds and Version values to identify the exact Office/365 installation version.Affected if The Office installation version is Microsoft 365 Apps (any unpatched version), Office 2019, Office LTSC 2021, or Office LTSC 2024.
-
Verify Office Online Server version (if applicable)If Office Online Server is deployed, check the version by reviewing the file properties of the Excel service executable or querying the farm version via the Office Online Server Administration Web App.Affected if Office Online Server version is earlier than 16.0.10417.20010.
-
Confirm exposure to untrusted Excel filesReview whether users in the environment routinely open Excel files from external sources, email attachments, or untrusted network locations. Check group policies under Administrative Templates > Microsoft Office Excel > Security settings for file handling restrictions.Affected if Users open Excel files from untrusted or external sources, which is the required trigger condition for this vulnerability to be exploited.
A system is affected if it runs any unpatched version of Microsoft Excel 2016 or later, Microsoft Office 2019 or later, Microsoft Office LTSC 2021/2024, Microsoft 365 Apps, or Office Online Server prior to version 16.0.10417.20010, and if users open specially crafted Excel files.
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 · scoped16.0.10417.20010
Apply the Microsoft security update for Excel (KB patch) as released in the corresponding security bulletin. Prioritize patching systems that handle untrusted Excel files.
For Microsoft 365: latest version via Microsoft Update; for Office 2016: KBXXXXXX (refer to CVE advisory); for Office 2019/2021/2024: latest patch via Update Channel; for Office Online Server: version 16.0.10417.20010 or later
- Open Microsoft Excel and go to File > Account > Update Options
- Select 'Update Now' to download and install the latest Microsoft updates
- Alternatively, manually download the security update from the Microsoft Update Catalog or the specific CVE advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-30376
- For Office Online Server, upgrade to version 16.0.10417.20010 or later by applying the latest Office Online Server cumulative update
- After updating, restart Excel and verify the version through File > Account > About Excel
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation4.0 h
- Testing4.0 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 $3,328.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-30376 — 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-2025-30376 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