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ExcelApplication · Microsoft

CVE-2012-2543

HIGH · 9.3 CVSS v2.0 Published 2012-11-14
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
Stack-based buffer overflow in Microsoft Excel 2007 SP2 and SP3 and 2010 SP1; Office 2011 for Mac; Excel Viewer; and Office Compatibility Pack SP2 and SP3 allows remote attackers to execute arbitrary code via a crafted spreadsheet, aka "Excel Stack Overflow 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

A stack-based buffer overflow vulnerability exists in Microsoft Excel's parsing of spreadsheet files. When Excel opens a specially crafted .xls file with malformed data, it causes a stack overflow that can be exploited to execute arbitrary code with the privileges of the user opening the file.

MitigationApply Microsoft security updates for this vulnerability (MS12-076) to all affected Office installations. Until patched, warn users against 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
ExcelApplication
Affected:= 2007= 2010
Excel ViewerApplication
Affected:all versions
OfficeApplication
Affected:= 2011
Office Compatibility PackApplication
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. Identify installed Microsoft Office products
    Open Control Panel > Programs and Features, or run 'Get-ItemProperty HKLM:\Software\Microsoft\Windows\CurrentVersion\Uninstall\* | DisplayName' in PowerShell to list installed Office-related software
    Affected if Any of the following are installed: Microsoft Excel, Microsoft Excel Viewer, Microsoft Office (2007, 2010, or 2011), or Microsoft Office Compatibility Pack
  2. Check Excel version if installed
    Open Excel, go to File > Account > About Excel, or check registry key HKLM\Software\Microsoft\Office\[Version]\Excel\InstallRoot
    Affected if Version is 2007, 2010, or if version falls within the 2007-2010 range without MS12-076 applied
  3. Check Microsoft Office version if installed without standalone Excel
    Open any Office app, go to File > Account > About, or check registry under HKLM\Software\Microsoft\Office\[Version]
    Affected if Version is 2011 for Mac, or version is 2007 or 2010 without MS12-076 applied
  4. Verify Excel Viewer installation
    Check for 'Microsoft Excel Viewer' in installed programs, or check registry under HKLM\Software\Microsoft\Excel Viewer
    Affected if Excel Viewer is installed at any version - all versions are affected
  5. Verify Office Compatibility Pack installation
    Check for 'Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint' in installed programs
    Affected if Compatibility Pack is installed at any version - all versions are affected
  6. Confirm vulnerability trigger condition
    The vulnerability is triggered only when Excel opens a specially crafted malformed .xls file
    Affected if User opens a malicious .xls file using a vulnerable, unpatched version of the affected products listed above

User is affected if any vulnerable version of Excel 2007/2010, Excel Viewer at any version, Office 2011, or Office Compatibility Pack is installed without MS12-076 security update applied, AND the user opens a specially crafted .xls file.

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 for this vulnerability (MS12-076) to all affected Office installations. Until patched, warn users against opening Excel files from untrusted sources.

Recommended fix High confidence

Apply the November 2012 Microsoft Security Bulletin MS12-076 patches for your respective product version.

  1. Apply Microsoft Security Bulletin MS12-076, which addresses this vulnerability in all affected Microsoft Office products.
  2. For Excel 2007: Ensure Service Pack 3 is installed, then apply the MS12-076 security update (KB2720184).
  3. For Excel 2010: Ensure Service Pack 1 is installed, then apply the MS12-076 security update (KB2720189).
  4. For Office 2011 for Mac: Apply the MS12-076 security update (KB2780342).
  5. For Excel Viewer: Apply MS12-076 security update (KB2726924) or upgrade to a supported version of Excel/Office.
  6. For Office Compatibility Pack: Apply the MS12-076 security update (KB2720184).
  7. Verify all patches are installed via Windows Update or Microsoft Update Catalog.
  8. For Office 2011 for Mac, use Microsoft AutoUpdate to check for and install available security updates.
Caveat Patches for legacy products (Excel Viewer, Office Compatibility Pack) may no longer be available; consider migrating to supported Office versions.

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

Fix this in Excel Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing4.0 h
  • Review / QA2.0 h
15.0 hours of engineering $2,640
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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-2012-2543 in production — separate from our analysis above.

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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