CVE-2009-0556

CRITICALNVD 8.89.0
EchelonGraph scoreHIGH confidence

“▲” beside the score: it is higher than NVD's CVSS score.

Score elevated to 9.0 because this CVE is listed on the CISA Known Exploited Vulnerabilities catalog (added 2026-01-07), indicating real-world exploitation has been confirmed by US federal agencies. NVD baseline CVSS 8.8 retained for reference. Confidence: HIGH.

Triggered by: CISA KEV (actively exploited)
Sources: CISA Known Exploited Vulnerabilities catalog, EPSS, GitHub Security Advisory, NVD CVSS v3
Trending — 3 sources updated this weekExploited in the wild
9.0EG
EchelonGraph verdictMitigate nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV) — the reason this is sooner than the SSVC decision on this page at low or medium mission impact
CISA-KEV: ExploitedEPSS PROB: 67%CVSS: 8.8Exploit: No code on recordExposed services: Not assessed

A fix is referenced (a reference tagged "Patch", often a source commit), but no release containing it is confirmed — find the release that contains it; until it is applied, mitigate (WAF / firewall / segmentation).

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."

CVSS v3
8.8
EG Score
9.0CRITICALhigh confidence
EG Risk
81
EG Risk 81/100

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed (value × EchelonGraph’s weight)
Severity90% × 45%
The EG Score, 9.0 of 10.
Exploitation100% × 40%
Fixed at 100% for a CISA KEV listing: EchelonGraph's rule.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low, Attend at medium and Act at high mission impact.
Exploitation active (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is referenced, but no release containing it is confirmed. Check the referenced fix and the vendor's advisory for a release that contains it and apply that within your standard update timelines at low, sooner than that at medium and as soon as possible at high mission impact; until then, restrict network exposure of the affected system or apply the vendor's mitigation.
EPSS PROB
67%
EPSS %ILE
99th
KEV
⚠ Exploited

SSVC (CISA's decision table, applied by EchelonGraph)Track at low, Attend at medium and Act at high mission impact.

A fix is referenced, but no release containing it is confirmed. Check the referenced fix and the vendor's advisory for a release that contains it and apply that within your standard update timelines at low, sooner than that at medium and as soon as possible at high mission impact; until then, restrict network exposure of the affected system or apply the vendor's mitigation.

Exploitation active (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)3 days & forensic triage if the affected system is publicly exposed; 14 days if it is not.

In CISA KEV yes (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

CISA 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.”

Quoted verbatim from CISA's Known Exploited Vulnerabilities catalog. CISA directs it at US federal civilian executive branch agencies under Binding Operational Directive (BOD) 26-04, which replaced BOD 22-01 on 10 June 2026; it is not EchelonGraph's advice. CISA's notes: https://learn.microsoft.com/en-us/security-updates/securitybulletins/2009/ms09-017 · https://nvd.nist.gov/vuln/detail/CVE-2009-0556

Published

April 3, 2009

Last Modified

April 22, 2026

Advisory Details (4)

Auto-updated May 2, 2026
⚠️ Actively exploited (CISA KEV, CISA Vulnrichment). Fix referenced — no release confirmed yet. Sources: cert.
Web page
http://www.securityfocus.com/bid/34351
Web page
http://www.securityfocus.com/archive/1/503453/100/0/threaded
CERT

VU#627331 - Microsoft Office PowerPoint code execution vulnerability

http://www.kb.cert.org/vuls/id/627331
Web page

About Secunia Research | Flexera

http://secunia.com/advisories/34572

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 53× in last 7d / 222× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 100 of 983 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 883 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-12 04:47 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  2. 2026-10-12 00:38 UTCEG score recompute
  3. 2026-10-12 00:38 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  4. 2026-10-11 20:27 UTCEG score recompute
  5. 2026-10-11 20:27 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  6. 2026-10-11 16:18 UTCEG score recompute
  7. 2026-10-11 16:18 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  8. 2026-10-11 13:38 UTCEPSS rescoreEPSS 67% · 99th percentile
  9. 2026-10-11 12:06 UTCEG score recompute
  10. 2026-10-11 12:06 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  11. 2026-10-11 07:57 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  12. 2026-10-11 03:46 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  13. 2026-10-10 23:36 UTCEG score recompute
  14. 2026-10-10 23:35 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  15. 2026-10-10 19:54 UTCEPSS rescoreEPSS 67% · 99th percentile
  16. 2026-10-10 19:23 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  17. 2026-10-10 15:12 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  18. 2026-10-10 11:03 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  19. 2026-10-10 06:53 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  20. 2026-10-10 02:45 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  21. 2026-10-09 22:36 UTCEG score recompute
  22. 2026-10-09 22:36 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  23. 2026-10-09 20:00 UTCEPSS rescoreEPSS 67% · 99th percentile
  24. 2026-10-09 18:26 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  25. 2026-10-09 14:14 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
Show 75 more
  1. 2026-10-09 10:02 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  2. 2026-10-09 05:53 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  3. 2026-10-09 01:44 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  4. 2026-10-08 21:35 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  5. 2026-10-08 17:25 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  6. 2026-10-08 13:16 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  7. 2026-10-08 09:06 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  8. 2026-10-08 04:57 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  9. 2026-10-08 00:48 UTCEG score recompute
  10. 2026-10-08 00:48 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  11. 2026-10-07 23:37 UTCEPSS rescoreEPSS 67% · 99th percentile
  12. 2026-10-07 20:38 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  13. 2026-10-07 16:28 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  14. 2026-10-07 12:17 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  15. 2026-10-07 08:08 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  16. 2026-10-07 03:59 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  17. 2026-10-06 23:49 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  18. 2026-10-06 19:40 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  19. 2026-10-06 15:31 UTCEG score recompute
  20. 2026-10-06 15:31 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  21. 2026-10-06 15:09 UTCEPSS rescoreEPSS 67% · 99th percentile
  22. 2026-10-06 11:20 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  23. 2026-10-06 07:11 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  24. 2026-10-06 03:02 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  25. 2026-10-05 22:52 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  26. 2026-10-05 18:43 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  27. 2026-10-05 14:32 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  28. 2026-10-05 10:23 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  29. 2026-10-05 06:15 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  30. 2026-10-05 02:05 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  31. 2026-10-04 21:55 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  32. 2026-10-04 17:45 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  33. 2026-10-04 13:36 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  34. 2026-10-04 09:27 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  35. 2026-10-04 05:17 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  36. 2026-10-04 01:08 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  37. 2026-10-03 20:59 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  38. 2026-10-03 16:50 UTCEG score recompute
  39. 2026-10-03 16:50 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  40. 2026-10-03 12:41 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  41. 2026-10-03 08:32 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  42. 2026-10-03 04:19 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  43. 2026-10-03 00:09 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  44. 2026-10-02 20:00 UTCEG score recompute
  45. 2026-10-02 20:00 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  46. 2026-10-02 15:51 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  47. 2026-10-02 11:41 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  48. 2026-10-02 07:29 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  49. 2026-10-02 03:20 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  50. 2026-10-01 23:10 UTCEG score recompute
  51. 2026-10-01 23:10 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  52. 2026-10-01 18:59 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  53. 2026-10-01 14:47 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  54. 2026-10-01 10:37 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  55. 2026-10-01 06:25 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  56. 2026-10-01 02:16 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  57. 2026-09-30 22:07 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  58. 2026-09-30 17:58 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  59. 2026-09-30 13:46 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  60. 2026-09-30 09:34 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  61. 2026-09-30 05:23 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  62. 2026-09-30 01:14 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  63. 2026-09-29 21:03 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  64. 2026-09-29 16:51 UTCEG score recompute
  65. 2026-09-29 16:51 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  66. 2026-09-29 12:42 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  67. 2026-09-29 08:33 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  68. 2026-09-29 04:24 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  69. 2026-09-29 00:14 UTCEG score recompute
  70. 2026-09-29 00:14 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  71. 2026-09-28 20:04 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  72. 2026-09-28 15:52 UTCEG score recompute
  73. 2026-09-28 15:52 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  74. 2026-09-28 11:42 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8
  75. 2026-09-28 07:31 UTCGHSA enrichmentGHSA-w25v-2mf8-86hr · GitHub severity HIGH · GitHub CVSS 8.8

Related CVEs(same CWE)

Frequently asked(6)

What is CVE-2009-0556?
CVE-2009-0556 is a critical-severity vulnerability; its CVE record was published on April 3, 2009. 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…
When was CVE-2009-0556 made public?
CVE-2009-0556 was made public on April 2, 2009: that is the date its CVE record's CNA, Microsoft Corporation, gives for when the vulnerability was made public. The CVE record itself was published on April 3, 2009. EchelonGraph's copy of the record carries a last-modified date of April 22, 2026; the record at its source may have been updated since.
Is CVE-2009-0556 actively exploited?
Yes. CISA added CVE-2009-0556 to the Known Exploited Vulnerabilities catalog on January 7, 2026, affecting Microsoft Office. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate attention. A fix is referenced, but no release containing it is confirmed. Check the referenced fix and the vendor's advisory for a release that contains it and apply that; until then, restrict network exposure of the affected system or apply the vendor's mitigation.
What is the CVSS score of CVE-2009-0556?
CVE-2009-0556 has a CVSS v3 base score of 8.8 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.0 (CRITICAL).
Which products are affected by CVE-2009-0556?
CVE-2009-0556 affects Microsoft Office.
How do I remediate CVE-2009-0556?
A fix for CVE-2009-0556 is referenced (a reference tagged "Patch", often a source commit), but EchelonGraph has no release containing it on record. Check that reference and the vendor's advisory for a release that contains the fix and update to it; until then, restrict network exposure of the affected system or apply the vendor's mitigation.

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