CVE-2011-1279
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 · uneditedMicrosoft Excel 2002 SP3 and 2003 SP3, Office 2004 and 2008 for Mac, and Open XML File Format Converter for Mac do not properly validate record information during parsing of Excel spreadsheets, which allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via a crafted spreadsheet, aka "Excel Out of Bounds WriteAV 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 confidenceThis is an out-of-bounds write vulnerability (WriteAV) in Microsoft Excel's file parsing logic. When Excel opens a crafted spreadsheet with malformed record information, it fails to properly validate the data before writing to memory, leading to memory corruption that can be exploited for arbitrary code execution.
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= 2002= 2003= 2004= 2008all versionsCVSS 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 checksWork through these to decide whether this CVE applies to you.
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Identify installed Microsoft Excel versionOpen Excel, go to Help > About Microsoft Excel, or run 'winword /?' from command prompt to check version, or check Programs and Features in Control Panel for Microsoft Excel entryAffected if Version displays as 2002 or 2003 (exact version numbers not provided in advisory)
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Identify installed Microsoft Office versionOpen any Office app, go to Help > About, or check Programs and Features for Microsoft Office entryAffected if Office version displays as 2004 or 2008 (for Mac) - note these are Mac versions; Windows Office versions would be checked via Excel directly
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Check for Microsoft Open Xml File Format ConverterCheck Programs and Features orApplications folder for 'Microsoft Open Xml File Format Converter' installationAffected if Converter is installed (all versions are affected per advisory)
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Confirm Excel file parsing is accessibleVerify that Excel application can be launched and users have ability to open spreadsheet files - the vulnerability triggers when Excel parses malformed record data in .xls filesAffected if Excel is installed and capable of opening files; the vulnerability exists in the file parsing logic regardless of file content
User is affected if Microsoft Excel 2002/2003, Microsoft Office 2004/2008, or Microsoft Open Xml File Format Converter (any version) is installed and can open spreadsheet 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 · scopedApply Microsoft security patches for this vulnerability and restrict users from opening untrusted or unexpected Excel files from external sources. Consider enterprise file sandboxing for Excel attachments.
Microsoft Office 2010 or later / Microsoft 365 (current supported version)
- Identify all systems with Excel 2002 SP3, Excel 2003 SP3, Office 2004 for Mac, Office 2008 for Mac, or Open XML File Format Converter installed
- Backup all critical data before making changes
- Uninstall the affected Microsoft Office and Excel versions from each system
- Install a supported, currently-maintained version of Microsoft Office (such as Office 2010 or later, or Microsoft 365)
- After installation, verify that Excel opens and functions correctly
- Apply all available Windows Updates or Microsoft Update patches to ensure the system is fully patched
- Test with a sample Excel spreadsheet to confirm functionality
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation3.0 h
- Implementation6.0 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 $3,984.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2011-1279 — 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-2011-1279 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