---
id: "CVE-2009-0557"
kind: "vulnerability"
aliases: ["CVE-2009-0557"]
title: "Excel in Microsoft Office 2000 SP3, Office XP SP3, Office 2003 SP3, and Office 2004 and 2008 for Mac; Excel in 2007\u2026"
severity: "critical"
cvss: 9.3
epss: 0.52845
exploited: true
status: "open"
category: "other"
products: [{"name": "Microsoft Office", "fixed": [], "affected": "", "ecosystem": "vendor"}, {"name": "microsoft office", "fixed": [], "affected": "= 2000", "ecosystem": "vendor"}, {"name": "microsoft office", "fixed": [], "affected": "= 2003", "ecosystem": "vendor"}, {"name": "microsoft office", "fixed": [], "affected": "= 2004", "ecosystem": "vendor"}, {"name": "microsoft office", "fixed": [], "affected": "= 2007", "ecosystem": "vendor"}, {"name": "microsoft office", "fixed": [], "affected": "= 2008", "ecosystem": "vendor"}, {"name": "microsoft office", "fixed": [], "affected": "= xp", "ecosystem": "vendor"}, {"name": "microsoft office compatibility pack", "fixed": [], "affected": "= 2007", "ecosystem": "vendor"}, {"name": "microsoft office excel viewer", "fixed": [], "affected": "", "ecosystem": "vendor"}, {"name": "microsoft office excel viewer", "fixed": [], "affected": "= 2003", "ecosystem": "vendor"}, {"name": "microsoft office sharepoint server", "fixed": [], "affected": "= 2007", "ecosystem": "vendor"}, {"name": "microsoft open xml file format converter", "fixed": [], "affected": "", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["excel", "exploited", "microsoft-office", "other", "windows"]
not_affected_if: ["patched-office"]
published_at: "2009-06-10T18:30:00+00:00"
first_seen_at: "2026-10-23T19:11:52+00:00"
updated_at: "2026-10-23T22:29:04+00:00"
sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2009-0557", "first_seen_at": "2026-10-23T19:11:52+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2009-0557", "first_seen_at": "2026-10-23T19:13:45+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2009-0557", "first_seen_at": "2026-10-23T22:29:04+00:00"}]
---

# Excel in Microsoft Office 2000 SP3, Office XP SP3, Office 2003 SP3, and Office 2004 and 2008 for Mac; Excel in 2007…

Microsoft Office has an object record corruption flaw that a crafted Excel file with a malformed record object can trigger. An attacker who gets a user to open that file can run code on the victim's machine.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:Microsoft Office affected ? fixed ?
- vendor:microsoft office affected = 2000 fixed ?
- vendor:microsoft office affected = 2003 fixed ?
- vendor:microsoft office affected = 2004 fixed ?
- vendor:microsoft office affected = 2007 fixed ?
- vendor:microsoft office affected = 2008 fixed ?
- vendor:microsoft office affected = xp fixed ?
- vendor:microsoft office compatibility pack affected = 2007 fixed ?
- vendor:microsoft office excel viewer affected ? fixed ?
- vendor:microsoft office excel viewer affected = 2003 fixed ?
- vendor:microsoft office sharepoint server affected = 2007 fixed ?
- vendor:microsoft open xml file format converter affected ? fixed ?

## Fix

Apply the Microsoft Office updates per vendor instructions, as CISA requires; the sources do not name the specific patch or fixed version.

## Timeline

- 2026-10-23T19:11:52+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2009-0557
- 2026-10-23T19:13:45+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2009-0557
- 2026-10-23T22:29:04+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2009-0557

## From the sources

Excel in Microsoft Office 2000 SP3, Office XP SP3, Office 2003 SP3, and Office 2004 and 2008 for Mac; Excel in 2007 Microsoft Office System SP1 and SP2; Open XML File Format Converter for Mac; Microsoft Office Excel Viewer 2003 SP3; Microsoft Office Excel Viewer; and Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats SP1 and SP2 allow remote attackers to execute arbitrary code via a crafted Excel file with a malformed record object, aka "Object Record Corruption Vulnerability."

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_