CVE-2009-3129
HIGHCISA KEVEPSS 100th pctlDescription
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 to fix
Actively exploited, no published fix found yet
CISA required action: Apply updates per vendor instructions.
Federal remediation due: 2022-03-24
Mitigation guidance may be in the linked vendor advisories in the References section below.
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CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Exploit Intelligence
Very high risk: more likely to be exploited than 100% of all known CVEs.
Microsoft Excel Featheader Record Memory Corruption Vulnerability
Microsoft Office Excel 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.
Apply updates per vendor instructions.
Remediation due: 2022-03-24
References
Related Vulnerabilities
Other CWE-787 (Out-of-bounds Write) vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2025-22457 | Critical | 9.0 | 100% | KEV + Ransom | Fix |
| CVE-2025-0282 | Critical | 9.0 | 100% | KEV + Ransom | - |
| CVE-2015-3113 | Critical | 9.8 | 100% | KEV | Fix |
| CVE-2021-20038 | Critical | 9.8 | 100% | KEV + Ransom | - |
| CVE-2023-4863 | High | 8.8 | 100% | KEV | Fix |
| CVE-2020-16040 | Medium | 6.5 | 100% | - | Fix |
Common questions
How do I fix CVE-2009-3129?
No published fix for CVE-2009-3129 has been found yet. It is on the CISA Known Exploited Vulnerabilities list; federal agencies must remediate by 2022-03-24. Apply the vendor's mitigations per CISA's guidance.
Is CVE-2009-3129 being actively exploited?
Yes. CVE-2009-3129 is listed in the CISA Known Exploited Vulnerabilities catalog, which means exploitation has been observed in the wild. US federal agencies were required to remediate it by 2022-03-24. Treat it as a priority whatever its CVSS score says.
How severe is CVE-2009-3129?
CVE-2009-3129 has a CVSS v3 base score of 7.8, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-22.