CVE-2025-29977
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 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 confidenceA use-after-free vulnerability exists in Microsoft Office Excel where memory is accessed after it has been freed, potentially allowing an attacker to execute arbitrary code locally on the affected system.
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.
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Confirm Microsoft Excel installationOpen Excel and go to File > Account > About Excel, or check Programs and Features in Control Panel for Microsoft Office installationsAffected if Excel or any Microsoft Office suite containing Excel is installed
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Determine Excel desktop application versionIn Excel, click File > Account > About Excel, or run 'winver' and look for Office version, or check HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office\ClickToRun\Configuration in RegistryAffected if Version is 2016, 2019, 2021, 2024, or part of Microsoft 365 Apps (all versions)
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Check Office Online Server version (if applicable)Open Office Online Server Management Shell and run Get-OfficeOnlineServerVersion, or check the file version of Microsoft.ServerBundle.dll in the installation pathAffected if Version is below 16.0.10417.20010
Your environment is affected if Microsoft Excel or any Office suite containing Excel is installed, including versions 2016, 2019, 2021, 2024, Microsoft 365 Apps, or Office Online Server versions below 16.0.10417.20010.
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 Microsoft security updates for Microsoft Office Excel as they become available through standard patch management processes.
Office Online Server: 16.0.10417.20010 or later; Other products: latest security updates via Microsoft Update
- 1. Ensure Microsoft Office is configured to receive updates from Microsoft Update or Windows Update
- 2. For Office Online Server, upgrade to version 16.0.10417.20010 or later
- 3. Apply the latest Microsoft Office security updates for your channel (Monthly Enterprise Channel, Semi-Annual Enterprise Channel, or Semi-Annual Channel)
- 4. Verify the update was installed successfully via Office app version information or Windows Update history
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-2025-29977 — 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-2025-29977 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