Historical catalog analysis: CISA added this entry on January 07, 2026. The entry reflects catalog information retrieved on August 31, 2026, not a snapshot archived on the inclusion date. Check current vendor guidance before acting.
What the vulnerability is
CVE-2009-0556 is a code injection vulnerability affecting Microsoft Office PowerPoint. The flaw stems from memory corruption that occurs when the application processes a PowerPoint file containing an OutlineTextRefAtom with an invalid index value. A remote attacker could leverage this memory corruption to execute arbitrary code on the target system.
Exposure and applicability
This vulnerability applies to environments running affected versions of Microsoft Office PowerPoint. The primary exposure path is the processing of a specially crafted PowerPoint file; therefore, any user or automated system that opens such a file is at risk. Because this involves legacy software components, infrastructure owners should identify whether these specific versions remain active in their environment, particularly on legacy workstations or air-gapped systems where updates may have been overlooked.
Remediation priorities
Based on the reported vulnerability, our analysis suggests the following prioritization for vulnerability management teams:
- Patch Application: The primary corrective action is to apply vendor mitigations as detailed in security bulletin MS09-017. This should be prioritized for all systems currently running vulnerable PowerPoint versions.
- Product Decommissioning: For legacy systems where patches cannot be applied or are unavailable, the most effective risk reduction strategy is to discontinue use of the affected product version entirely.
- Cloud Service Alignment: Organizations utilizing cloud-based delivery of Office should ensure their configurations align with BOD 22-01 guidance to ensure managed updates are enforced.
How to validate remediation
To verify that exposure has been reduced, defenders should move beyond simple version checks. While confirming a version number is a starting point, it does not prove the specific patch was successfully applied and active in memory.
Validation should include:
* Patch Verification: Confirming through system logs or update management consoles that MS09-017 (or its equivalent successor) has been successfully installed.
* Configuration Audit: Verifying that legacy, unpatched versions of PowerPoint have been removed from the environment or are blocked from executing via application control policies.
Limits and open questions
Applying a patch could reduce the likelihood of exploitation, but it does not eliminate all risks associated with processing untrusted files. Residual risk remains if attackers find alternative paths to trigger memory corruption within the same component. Additionally, while this vulnerability is listed in the CISA Known Exploited Vulnerabilities catalog, the source indicates that its use in known ransomware campaigns is currently unknown.
Source and editorial note
CVE-2009-0556: Microsoft Office PowerPoint Code Injection Vulnerability · Source date: January 07, 2026 · Retrieved August 31, 2026.
Material facts are tied to the cited primary source. Recommendations are independent defensive analysis unless attributed to the source. Confirm consequential decisions against current authoritative guidance.
Archive date: January 10, 2026. The displayed post date is assigned three days after the source date to organize this retrospective archive; it does not mean this site published the analysis then. First published by this site: September 24, 2026 at 00:29 UTC.
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