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Compatibility Pack Word Excel PowerpointApplication · Microsoft

CVE-2009-3131

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 allow remote attackers to execute arbitrary code via a spreadsheet with a crafted formula embedded in a cell, aka "Excel Formula Parsing 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

Microsoft Excel contains a memory corruption vulnerability in its formula parsing engine when processing specially crafted spreadsheet files. When a cell contains a maliciously constructed formula, the parser fails to properly handle memory allocation, leading to heap-based buffer overflow that can be exploited for arbitrary code execution with user privileges.

MitigationApply Microsoft security updates from MS09-067 (Excel security bulletin) to all affected Office installations. Until patched, restrict opening Excel attachments from untrusted sources and enable Protected View in Office Trust Center settings.

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 if Microsoft Excel is installed
    Open Control Panel > Programs and Features, or run 'Get-ItemProperty HKLM:\Software\Microsoft\Windows\CurrentVersion\Uninstall\* | Select-Object DisplayName' in PowerShell to list installed programs. Look for Microsoft Excel, Microsoft Office, Microsoft Compatibility Pack, or Microsoft Excel Viewer.
    Affected if Any of the affected products listed in the CVE are installed (Excel 2002, 2003, 2007; Excel Viewer; Office 2004, 2008; Compatibility Pack 2007; Open XML File Format Converter).
  2. Identify the exact installed version
    Open Excel, go to Help > About Microsoft Excel, or run 'winword.exe /?' from Command Prompt if using Office. Record the full version number (for example, 11.0.xxxx for Excel 2002, 12.0.xxxx for Excel 2007).
    Affected if The installed version falls within these ranges: Excel 2002 (11.x), Excel 2003 (11.x), Excel 2007 (12.x); Excel Viewer all versions; Office 2004 (11.x), Office 2008 (12.x); Compatibility Pack 2007 (12.x); Open XML File Format Converter any version.
  3. Verify if MS09-067 security update is installed
    Open Control Panel > Programs and Features > View installed updates, or run 'Get-HotFix | Where-Object {$_.Description -eq "Security Update"}' in PowerShell. Look for KB976382 (the update for MS09-067).
    Affected if The security update KB976382 from MS09-067 is NOT installed. If missing, the system remains vulnerable to CVE-2009-3131.
  4. Confirm Excel file handling is enabled
    Open Excel, go to File > Options > Trust Center > Trust Center Settings > Protected View. Check if Protected View is enabled for files from the internet and other potentially unsafe locations.
    Affected if Protected View is disabled or users routinely bypass warnings and enable editing on untrusted files, increasing exposure to the vulnerability.

A system is affected if any of the listed vulnerable products are installed AND the MS09-067 security update (KB976382) has not been applied.

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 Microsoft security updates from MS09-067 (Excel security bulletin) to all affected Office installations. Until patched, restrict opening Excel attachments from untrusted sources and enable Protected View in Office Trust Center settings.

Recommended fix High confidence

Microsoft 365 Apps, Office 2019, or Office 2016 (any currently supported Office version)

  1. 1. Identify all Microsoft Office Excel installations and Excel Viewer instances on affected systems (Excel 2002, 2003, 2007, Office 2004 for Mac, Office 2008 for Mac, Open XML File Format Converter for Mac, Office Excel Viewer all versions, Office Compatibility Pack 2007).
  2. 2. For Windows systems: Check for and apply the relevant Microsoft security patches if still available (historically addressed via MS09-067 and MS09-021).
  3. 3. For systems where patches are no longer available (end-of-life products): Uninstall the affected Office versions.
  4. 4. Install a currently supported Microsoft Office version (Office 2016, 2019, or Microsoft 365 Apps).
  5. 5. Verify that the new Office installation is updated to the latest cumulative updates.
  6. 6. Test that Excel files can be opened and formulas parsed correctly in the new version.
Caveat Legacy file formats and macros may need updating; older Office versions (2004/2008 for Mac, Excel Viewer) are discontinued and require complete replacement with modern Office

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
  • Consultation0.5 h
  • Implementation1.5 h
  • Testing1.0 h
  • Review / QA1.0 h
4.0 hours of engineering $750
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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-2009-3131 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