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Compatibility Pack Word Excel PowerpointApplication · Microsoft

CVE-2009-3134

HIGH · 9.3 CVSS v2.0 Published 2009-11-11
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

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 do not properly parse the Excel file format, which allows remote attackers to execute arbitrary code via a spreadsheet with a malformed record object, aka "Excel Field Sanitization 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

This is a memory corruption vulnerability in Microsoft Excel's file parsing logic. When Excel opens a specially crafted .xls spreadsheet containing a malformed record object, it fails to properly sanitize input, allowing an attacker to overwrite memory and execute arbitrary code. The vulnerability is triggered when users open a malicious spreadsheet file, typically received via email or downloaded from untrusted sources.

MitigationApply vendor patches (MS09-067) if running affected legacy versions; for current systems, upgrade to supported Office versions and enable Microsoft Office File Validation. Avoid opening Excel files from untrusted 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
Compatibility Pack Word Excel PowerpointApplication
Affected:= 2007
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
Network
Complexity
M
Authentication
None
Confidentiality
Complete
Integrity
Complete
Availability
Complete

AV:N/AC:M/Au:N/C:C/I:C/A:C

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. Check Microsoft Excel version
    Open Excel, go to Help > About Microsoft Excel, or run 'winword /?' from command prompt to check version. On Windows, also check Add/Remove Programs or Programs and Features for installed Microsoft Office/Excel versions.
    Affected if Version is 2002, 2003, or 2007 (exact versions match 2002, 2003, or 2007)
  2. Check Microsoft Office version (Windows)
    Open any Office app, go to Help > About, or check Programs and Features for Microsoft Office entry. Note that Office 2004 and 2008 (Mac) are also affected.
    Affected if Office version is 2004 or 2008 (Mac versions) or matches the Excel versions listed above
  3. Check Microsoft Excel Viewer installation
    Check Programs and Features or look for Excel Viewer executable (XLVIEW.EXE) in Program Files. This applies to all versions and specifically version 2003.
    Affected if Microsoft Excel Viewer is installed (any version, particularly version 2003)
  4. Check Microsoft Compatibility Pack installation
    Check Programs and Features for 'Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint' or look for ExcelCnv.exe in Program Files.
    Affected if Microsoft Compatibility Pack version 2007 is installed
  5. Check Microsoft Open Xml File Format Converter
    Check Programs and Features for 'Microsoft Open XML File Format Converter' or look for converter executable.
    Affected if Microsoft Open XML File Format Converter is installed (any version)
  6. Verify ability to open .xls files
    Check if Excel or Excel Viewer is configured as default handler for .xls files, or confirm user can manually open such files.
    Affected if Any affected Excel component can open .xls spreadsheet files

You are affected if any of the following are installed: Excel 2002, 2003, or 2007; Office 2004 or 2008; Excel Viewer (any version, especially 2003); Compatibility Pack 2007; or Open XML File Format Converter, AND the application can open .xls files.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply vendor patches (MS09-067) if running affected legacy versions; for current systems, upgrade to supported Office versions and enable Microsoft Office File Validation. Avoid opening Excel files from untrusted sources.

Recommended fix High confidence

Upgrade to a supported Microsoft Office version (Microsoft 365, Office 2019, or later). For legacy systems, apply MS09-067 security update and then migrate to supported Office versions as older versions are past end of support.

  1. Identify the exact Office/Excel version currently installed
  2. For Office 2002/2003/2007 Windows: Apply Microsoft Security Update MS09-067 (or subsequent service packs that include the fix)
  3. For Office 2004/2008 for Mac: Apply the corresponding Apple security updates
  4. For Office Excel Viewer: Upgrade to a supported version or replace with Microsoft 365/Office 365
  5. For Compatibility Pack: Apply MS09-067 or upgrade to Microsoft 365
  6. After patching, verify the update was successfully applied via Windows Update or Office Update
  7. As a temporary workaround, do not open untrusted Excel files from unknown sources
Caveat Office 2004/2008 for Mac and Office 2007 are past end of support; migrating to Microsoft 365 may require subscription changes and feature adjustments. Ensure file format compatibility with legacy .xls files.

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

Fix this in Compatibility Pack Word Excel Powerpoint Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
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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-2009-3134 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