How severe is CVE-2009-3129?

CVE-2009-3129 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2009-3129 being actively exploited?

Yes. CVE-2009-3129 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2022-03-03, which means active exploitation has been confirmed. It should be prioritised for remediation.

What products are affected by CVE-2009-3129?

CVE-2009-3129 primarily affects Microsoft Excel. In total, 10 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2009-3129?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.

Does CVE-2009-3129 have an EU (EUVD) identifier?

Yes. CVE-2009-3129 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2009-3112. It is also flagged as exploited in the EUVD (since 2022-03-03).

When was CVE-2009-3129 published?

CVE-2009-3129 was published on 2009-11-11 and last updated on 2026-06-16.

CVE-2009-3129

CVE-2009-3129 is a high-severity vulnerability in Microsoft Excel with a CVSS 3.x base score of 7.8. It is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, confirming it has been exploited in the wild (added 2022-03-03). The underlying weakness is classified as CWE-787.

Key facts

Severity: High (CVSS 3.x base score 7.8)
CVSS v2: 9.3
EPSS exploit prediction: 86% (100th percentile)
Actively exploited: Yes — listed in CISA KEV (added 2022-03-03)
EU (EUVD) id: EUVD-2009-3112
EU exploitation: Flagged exploited in the ENISA EU Vulnerability Database (since 2022-03-03)
Weakness: CWE-787
Affected product: Microsoft Excel
Published: 2009-11-11
Last modified: 2026-06-16

Description

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."

Frequently asked questions

What is CVE-2009-3129?: 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."
How severe is CVE-2009-3129?: CVE-2009-3129 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2009-3129 being actively exploited?: Yes. CVE-2009-3129 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2022-03-03, which means active exploitation has been confirmed. It should be prioritised for remediation.
What products are affected by CVE-2009-3129?: CVE-2009-3129 primarily affects Microsoft Excel. In total, 10 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2009-3129?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.
Does CVE-2009-3129 have an EU (EUVD) identifier?: Yes. CVE-2009-3129 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2009-3112. It is also flagged as exploited in the EUVD (since 2022-03-03).
When was CVE-2009-3129 published?: CVE-2009-3129 was published on 2009-11-11 and last updated on 2026-06-16.

References

Affected products (10)

cpe:2.3:a:microsoft:excel:2002:sp3:*:*:*:*:*:*
cpe:2.3:a:microsoft:excel:2003:sp3:*:*:*:*:*:*
cpe:2.3:a:microsoft:excel:2007:sp1:*:*:*:*:*:*
cpe:2.3:a:microsoft:excel:2007:sp2:*:*:*:*:*:*
cpe:2.3:a:microsoft:excel_viewer:-:sp1:*:*:*:*:*:*
cpe:2.3:a:microsoft:excel_viewer:-:sp2:*:*:*:*:*:*
cpe:2.3:a:microsoft:excel_viewer:2003:sp3:*:*:*:*:*:*
cpe:2.3:a:microsoft:office:2004:*:*:*:*:macos:*:*
cpe:2.3:a:microsoft:office:2008:*:*:*:*:macos:*:*
cpe:2.3:a:microsoft:open_xml_file_format_converter:*:*:*:*:*:macos:*:*

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