What is CVE-2009-0556?

CVE-2009-0556 is a high-severity vulnerability in Microsoft Office Powerpoint, classified under Code Injection. CVSS score: 8.8/10. Published 2009-04-03.

How severe is CVE-2009-0556?

High severity. CVSS v3 base score is 8.8 out of 10.

Is CVE-2009-0556 known to be exploited?

Yes. CVE-2009-0556 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-01-07), indicating it is being actively exploited. 1 public proof-of-concept repositories are indexed.

RCE in Microsoft Office Powerpoint

CVE-2009-0556

Microsoft Office PowerPoint 2000 SP3, 2002 SP3, and 2003 SP3, and PowerPoint in Microsoft Office 2004 for Mac, allows remote attackers to execute arbitrary code via a PowerPoint file with an OutlineTextRefAtom containing an an invalid index value that triggers memory corruption, as exploited in the wild in April 2009 by Exploit:Win32/Apptom.gen, aka "Memory Corruption Vulnerability."

Vulnerability class: RCE (Remote Code Execution)

Published 2009-04-03 · last modified 2026-06-16.

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.673 (99.3th percentile), scored 2026-10-18.

High probability of exploitation in the next 30 days — patch promptly. 99th percentile — 99.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.673 · newest: 0.673 · change: 0.000

Affected products

Microsoft Office Powerpoint — versions 2004
Microsoft Powerpoint — versions 2000, 2002, 2003

Weakness classification (CWE)

CWE-94 — Code Injection

CISA KEV (Known Exploited Vulnerabilities)

This CVE is on the CISA KEV catalog, added on 2026-01-07. CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.

BOD 22-01 due date: 2026-01-28.

Required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Public proof-of-concept exploits

ARPSyndicate/cve-scores

References

www.zerodayinitiative.com/advisories/ZDI-09-019 (Third Party Advisory)
blogs.technet.com/mmpc/archive/2009/04/02/new-0-day-exploits-using-powerpoint-f… (Vendor Advisory)
www.vupen.com/english/advisories/2009/1290 (vdb-entry, Broken Link)
osvdb.org/53182 (vdb-entry, Broken Link)
docs.microsoft.com/en-us/security-updates/securitybulletins/2009/ms09-017 (vendor-advisory, Vendor Advisory)
exchange.xforce.ibmcloud.com/vulnerabilities/49632 (Third Party Advisory, vdb-entry)
www.securityfocus.com/bid/34351 (vdb-entry, Broken Link)
www.vupen.com/english/advisories/2009/0915 (vdb-entry, Vendor Advisory)
blogs.technet.com/msrc/archive/2009/04/02/microsoft-security-advisory-969136.as… (Vendor Advisory)
blogs.technet.com/srd/archive/2009/04/02/investigating-the-new-powerpoint-issue… (Vendor Advisory)

Frequently asked questions

What is CVE-2009-0556?: CVE-2009-0556 is a high-severity vulnerability in Microsoft Office Powerpoint, classified under Code Injection. CVSS score: 8.8/10. Published 2009-04-03.
How severe is CVE-2009-0556?: High severity. CVSS v3 base score is 8.8 out of 10.
Is CVE-2009-0556 known to be exploited?: Yes. CVE-2009-0556 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-01-07), indicating it is being actively exploited. 1 public proof-of-concept repositories are indexed.