CVE-2009-0556
Microsoft Office PowerPoint Code Injection Vulnerability
Microsoft Office
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."
Exploitation status
CISA Known Exploited Vulnerabilities
Listed by CISA on 7 January 2026. US federal agencies were required to remediate it by 28 January 2026.
EPSS — exploitation probability
FIRST puts the probability of exploitation activity in the next 30 days at 67.3%, which is higher than 99.3% of all scored vulnerabilities. EPSS is a forecast of activity, not a measure of severity, and it is rescored daily.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Frequently asked questions
Is CVE-2009-0556 being exploited by ransomware groups?
No ransomware group in this database is currently recorded as exploiting CVE-2009-0556.
What does CVE-2009-0556 affect?
CVE-2009-0556 affects Microsoft Office. 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."
How severe is CVE-2009-0556?
CVE-2009-0556 is rated HIGH with a CVSS base score of 8.8. EPSS puts the probability of exploitation in the next 30 days at 67.3%, higher than 99.3% of all scored vulnerabilities. It is listed in the CISA Known Exploited Vulnerabilities catalog, with a federal remediation deadline of 28 January 2026.
How should organisations respond to CVE-2009-0556?
Apply the vendor patch for Microsoft Office as the first priority, and treat any internet-facing instance as the most urgent. Because this vulnerability is associated with ransomware activity, also review whether the affected systems were reachable before patching, rather than assuming that patching alone closes the incident.