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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 24 Mar 2022.
ExcelApplication · Microsoft

CVE-2009-3129

HIGH · 7.8 CVSS v3.1 Published 2009-11-11
Patch available
A vendor patch is available. No clean upgrade release — apply the published patch.
See remediation →
97/100
Remediation priority · Urgent
In the wild High EPSS Public exploit No privileges Patch available

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 · unedited
Microsoft Office Excel 2002 SP3, 2003 SP3, and 2007 SP1 and SP2; Office 2004 and 2008 for Mac; Open XML File Format Converter for Mac; Office Excel Viewer 2003 SP3; Office Excel Viewer SP1 and SP2; and Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats SP1 and SP2 allows remote attackers to execute arbitrary code via a spreadsheet with a FEATHEADER record containing an invalid cbHdrData size element that affects a pointer offset, aka "Excel Featheader Record Memory Corruption Vulnerability."

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 · high confidence

Memory corruption vulnerability in Microsoft Excel where a specially crafted spreadsheet contains a FEATHEADER record with an invalid cbHdrData size element that corrupts a pointer offset, allowing remote code execution.

MitigationApply Microsoft security update MS09-067 to affected Office products, or upgrade to patched versions of Office Excel. Avoid opening untrusted .xls files from unknown sources.

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 data
ExcelApplication
Affected:= 2002= 2003= 2007
Excel ViewerApplication
Affected:all versions= 2003
OfficeApplication
Affected:= 2004= 2008
Open Xml File Format ConverterApplication
Affected:all versions

CVSS 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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed Microsoft Excel version
    Open Excel, go to Help > About Microsoft Excel, or run 'winword.exe /?' from command line, or check Programs and Features in Control Panel for Office/Excel version
    Affected if The installed Excel version is 2002 (version 10), 2003 (version 11), or 2007 (version 12)
  2. Identify installed Microsoft Office version
    Open any Office application, go to Help > About, or check Programs and Features for Microsoft Office version
    Affected if The installed Office version is 2004 for Mac (version 11) or 2008 for Mac (version 12)
  3. Check for Microsoft Excel Viewer
    Check Programs and Features or search for ExcelView.exe on the system
    Affected if Microsoft Excel Viewer of any version is installed
  4. Check for Open Xml File Format Converter
    Search for 'Microsoft Open Xml File Format Converter' in Programs and Features or look for the converter application
    Affected if Open Xml File Format Converter is installed (any version)

A system is affected if any version of Excel 2002, 2003, or 2007, Office 2004 or 2008, Excel Viewer, or Open Xml File Format Converter is installed, as all these versions contain the vulnerable FEATHEADER record parsing code.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 · scoped
Patch available Apply the vendor patch
Vendor patch docs.microsoft.com →
Interim mitigation

Apply Microsoft security update MS09-067 to affected Office products, or upgrade to patched versions of Office Excel. Avoid opening untrusted .xls files from unknown sources.

Recommended fix High confidence

Microsoft Office 2019 or Microsoft 365 (current supported versions)

  1. 1. Back up all important Excel files and documents before making any changes.
  2. 2. Uninstall Microsoft Office versions 2002, 2003, 2007, 2004, and 2008 which are no longer supported.
  3. 3. Download and install a currently supported version of Microsoft Office (such as Microsoft 365, Office 2021, or Office 2019).
  4. 4. Ensure Windows or macOS is also updated to a supported version.
  5. 5. After installation, verify that Excel functions correctly by opening existing spreadsheets.
  6. 6. Enable automatic updates for Microsoft Office to receive future security patches.
Caveat Upgrading from Office 2002-2008 may require file format migration; older .xls files will need to be opened and saved in newer formats; some legacy features or macros may require review or updating

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Excel Exploited in the wild — priority engagement
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
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Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2009-3129 in production — separate from our analysis above.

No notes yet

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What this is

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.

What belongs here
  • 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