# CVE-2009-0238: Microsoft Excel remote code execution via malformed object

Source: https://junglewise.ai/threats/cve-2009-0238-microsoft-excel-remote-code-execution-via-malformed-object  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-04-14. Updated: 2026-05-15  
License: CC BY 4.0 with a link back

CVE-2009-0238 · Severity: critical · CVSS 9.3 · Exploited in the wild · Published 2026-04-14

Microsoft Excel is a widely used spreadsheet application for data analysis and reporting. A vulnerability exists where an attacker can take full control of a user's computer if the user opens a specially crafted Excel file. This could lead to the theft of sensitive data, installation of malware, or complete disruption of business operations.

Technologies: [Microsoft Excel](https://junglewise.ai/threats/technologies/excel), [Microsoft Office](https://junglewise.ai/threats/technologies/office). Vendors: [Microsoft](https://junglewise.ai/threats/vendors/microsoft).

## Quick answers

**Is CVE-2009-0238 exploited in the wild?** Yes. CVE-2009-0238 is known to be exploited in the wild, first recorded on 14 April 2026. Treat it as urgent.

**How severe is CVE-2009-0238?** Critical severity, with a CVSS score of 9.3, published 14 April 2026.

**Which products and versions are affected?** Microsoft Excel 2000 SP3, 2002 SP3, 2003 SP3, 2007 SP1; Microsoft Excel Viewer 2003 Gold and SP3; Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats SP1; Microsoft Office for Mac 2004, 2008.

**Is there a fix for CVE-2009-0238?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2009-0238 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2009-0238?** Check whether you run Microsoft Excel, Microsoft Excel Viewer, Microsoft Office or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A remote code execution vulnerability exists in multiple versions of Microsoft Excel due to improper handling of objects within Excel documents. The flaw is triggered when the application attempts to access an invalid object within a malformed file, leading to memory corruption or code injection (CWE-94). An attacker can exploit this by tricking a user into opening a malicious .xls file, typically delivered via email or a malicious website. Successful exploitation allows for arbitrary code execution in the context of the logged-in user. This vulnerability was notably exploited in the wild by the Trojan.Mdropper.AC malware. Patches were released by Microsoft under security bulletin MS09-009.

## Affected products

- Microsoft Excel 2000 SP3, 2002 SP3, 2003 SP3, 2007 SP1
- Microsoft Excel Viewer 2003 Gold and SP3
- Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats SP1
- Microsoft Office for Mac 2004, 2008

## Timeline

- 2009-02-23: exploited: Exploited in the wild by Trojan.Mdropper.AC
- 2009-04-14: advisory: Microsoft released security bulletin MS09-009
- 2026-04-14: kev added: Added to CISA Known Exploited Vulnerabilities Catalog

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