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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."

CVSS
7.8Highscored by CISA
Exploited in the wild
Yes, in CISA KEV since 3 Mar 2022CISA deadline for US federal agencies: 24 Mar 2022public exploit code
EPSS
84.0%chance of exploitation in the next 30 daystop 0.4% of scored CVEsFIRST score of 11 Nov 2026
Fix
Patch availablesee the advisories in the references
Published
11 Nov 2009analysed here 12 Nov 2026

Do first. Apply updates per vendor instructions. (CISA's required action for this KEV entry)

Summary

Triage

Attack surface
Server-side
Exploitable
At runtime
Attack vector
local
Weakness
Can a WAF block it?
No. See why

The summary, impact and action text on this page are written by our AI analysis pipeline, or taken from the NVD description when a CVE was imported from NVD. They are not the vendor's wording: check them against the sources. A longer AI executive summary and technical analysis are generated for signed-in accounts on the Max plan.

Affected products

Products named in our analysis

  • microsoft:excel
  • microsoft:excel_viewer
  • microsoft:office
  • microsoft:open_xml_file_format_converter

Fix and mitigation

WAF and other mitigations

Can a WAF block it? No. The attack needs local access to the machine, so a WAF is not on its path.

Also consider: patch

Based on the attack vector (local or physical access). We check Cloudflare, AWS, Google Cloud Armor and Azure; for Akamai, Imperva, Fastly, F5, ask your vendor.

Remediation steps (AI-written)

Step-by-step remediation is generated for accounts on the Max plan, for CVEs that match a technology in their stack. Add this technology to your stack to see the fix checklist.

Exploitation evidence

CISA KEV catalog
Listed since 3 Mar 2022.
CISA due date
24 Mar 2022, the remediation deadline for US federal agencies
CISA required action
Apply updates per vendor instructions.
Public exploit code
Yes: 2 on Exploit-DB · 1 Metasploit module
CISA SSVC
exploitation active, automatable no, technical impact totalAssessed by CISA 10 Feb 2025 (SSVC 2.0.3). Exploitation is none, poc (public proof of concept) or active.

Exploit-DB

Metasploit

Listed so you can judge urgency, not as a recommendation to run anything. GitHub “proofs of concept” are unvetted: some are fake or carry malware. Exploit-DB marks the entries its staff verified.

Timeline

  1. 11 Nov 2009Published
  2. 21 Aug 2010First public exploit or proof of concept282 days (about 9 months) later
  3. 3 Mar 2022Added to CISA KEV (exploited in the wild)4,212 days (about 12 years) later
  4. 24 Mar 2022CISA remediation due date (US federal agencies)21 days later
  5. 10 Feb 2025CISA SSVC assessment: exploitation active1,055 days (about 3 years) later
  6. 22 Oct 2025CVE record last updated253 days (about 8 months) later
  7. 12 Nov 2026Analysed by vulneraibility.com387 days (about 1 year) later

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

MetricValueWhat it means
Attack vectorLocalLocal access required (shell, logged-in user).
Attack complexityLowRepeatable attack, no special conditions.
Privileges requiredNoneThe attacker needs no prior access.
User interactionRequiredA victim must click, open or otherwise cooperate.
ScopeUnchangedImpact stays within the vulnerable component.
ConfidentialityHighTotal data disclosure possible.
IntegrityHighComplete modification possible.
AvailabilityHighFull outage possible.

Common questions

Is CVE-2009-3129 being exploited?

Yes. CVE-2009-3129 appears in CISA's Known Exploited Vulnerabilities catalog, which means exploitation in the wild has been confirmed and reported. Treat it as active rather than theoretical, and patch it ahead of higher-scoring vulnerabilities that carry no exploitation evidence.

How severe is CVE-2009-3129?

CVE-2009-3129 is rated High with a CVSS score of 7.8. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.

Is there a patch for CVE-2009-3129?

Yes. A fix has been recorded for CVE-2009-3129. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.

What does CVE-2009-3129 affect?

CVE-2009-3129 affects microsoft:excel, microsoft:excel_viewer, microsoft:office, microsoft:open_xml_file_format_converter. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.

Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.

References

NVDCVE.orgCVE DetailsSource

11 references in the CVE record, grouped by the tags the record gives them.

Advisories (3)

Exploits (1)

Other links (7)

Show 1 more
  • cisa.gov /known-exploited-vulnerabilities-catalog?field_cve=CVE-2009-3129

Where the data on this page comes from

Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.

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