CVE-2009-4020

HIGHCVSS v2 · 7.87.8—
EchelonGraph scoreLOW confidence

This CVE was only ever scored under CVSS v2.0. NVD CVSS v2.0 base 7.8 — v2 rates that HIGH (v2 bands: LOW 0.0–3.9 / MEDIUM 4.0–6.9 / HIGH 7.0–10.0; v2 has no CRITICAL band). Vector AV:N/AC:L/Au:N/C:N/I:N/A:C. CVSS v2 is an older, coarser metric than v3.1/v4.0 (no Scope, no User Interaction, no Attack Requirements), so it is not directly comparable to a v3 or v4 score. NVD has never re-scored this record under v3. EPSS predicts 5.0% exploitation probability in the next 30 days, which is reflected in EG Risk but does not lift the v2 base. Confidence: LOW.

Sources: epss, nvd_v2
7.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 5%CVSS v2: 7.8Exploit: None knownExposed: 0

A fix is available — apply it.

Stack-based buffer overflow in the hfs subsystem in the Linux kernel 2.6.32 allows remote attackers to have an unspecified impact via a crafted Hierarchical File System (HFS) filesystem, related to the hfs_readdir function in fs/hfs/dir.c.

CVSS v2.0 (legacy)
7.8HIGHNVD never assigned a CVSS v3 rating to this CVE
EG Score
7.8(low)
EG Risk
42(Track)
EG Risk 42/100SSVC: Track

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
Severity78% × 45%
Exploitation5% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
5%
EPSS %ILE
92%
KEV
Not listed

Published

December 4, 2009

Last Modified

April 23, 2026

References (30)

Vendor Advisories for CVE-2009-4020(2)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(3)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulinux-image-2.6.31-19-ia64 (2.6.31-19.56) @ karmic2026-05-30ubuntu
redhatkernel-0:2.6.9-89.0.20.EL2010-02-02redhat
redhatkernel-0:2.6.18-164.11.1.el52010-01-19redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(2 across 1 ecosystem)
Debian:4.0(2)
PackageVulnerable rangeFixed inDependents
linux-2.62.6.18.dfsg.1-12 ... 2.6.18.dfsg.1-26etch1 (38 versions)2.6.18.dfsg.1-26etch2—
linux-2.6.242.6.24-5~etchnhalf.1 ... 2.6.24-6~etchnhalf.9etch2 (15 versions)2.6.24-6~etchnhalf.9etch3—

Weakness Classification(1)

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

Additional Vendor Advisories

(1)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 2× in last 7d / 9× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. 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. Most recent first.

Showing the most recent 100 of 108 total refreshes for this CVE.

  1. 2026-08-25 13:43 UTCEPSS rescore
  2. 2026-08-19 16:58 UTCEPSS rescore
  3. 2026-08-15 01:24 UTCEPSS rescore
  4. 2026-08-09 13:41 UTCEPSS rescore
  5. 2026-08-08 16:31 UTCEPSS rescore
  6. 2026-08-06 13:41 UTCEPSS rescore
  7. 2026-08-03 10:28 UTCEPSS rescore
  8. 2026-07-30 16:22 UTCEPSS rescore
  9. 2026-07-30 01:26 UTCEPSS rescore
  10. 2026-07-26 13:39 UTCEG score recompute▲ 7.80
  11. 2026-07-25 14:12 UTCEPSS rescore
  12. 2026-07-24 14:12 UTCEPSS rescore
  13. 2026-07-23 14:14 UTCEPSS rescore
  14. 2026-07-23 01:00 UTCEG score recompute
  15. 2026-07-23 00:37 UTCEG score recompute
  16. 2026-07-23 00:04 UTCEG score recompute
  17. 2026-07-22 21:43 UTCEG score recompute
  18. 2026-07-22 14:03 UTCEPSS rescore
  19. 2026-07-21 15:20 UTCEPSS rescore
  20. 2026-07-20 17:03 UTCEPSS rescore
  21. 2026-07-20 17:03 UTCEPSS rescore
  22. 2026-07-18 09:59 UTCEPSS rescore
  23. 2026-07-16 16:58 UTCEPSS rescore
  24. 2026-07-15 16:54 UTCEPSS rescore
  25. 2026-07-15 16:54 UTCEPSS rescore
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  1. 2026-07-15 01:55 UTCEPSS rescore
  2. 2026-07-13 22:25 UTCEPSS rescore
  3. 2026-07-13 06:07 UTCEPSS rescore
  4. 2026-07-11 08:22 UTCEPSS rescore
  5. 2026-07-11 08:22 UTCEPSS rescore
  6. 2026-07-09 19:04 UTCEPSS rescore
  7. 2026-07-08 15:10 UTCEPSS rescore
  8. 2026-07-06 16:23 UTCEPSS rescore
  9. 2026-07-06 02:19 UTCEPSS rescore
  10. 2026-07-06 02:19 UTCEPSS rescore
  11. 2026-07-05 02:26 UTCEPSS rescore
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  13. 2026-07-04 06:27 UTCEPSS rescore
  14. 2026-07-01 15:02 UTCEPSS rescore
  15. 2026-06-30 23:19 UTCEPSS rescore
  16. 2026-06-28 14:03 UTCEPSS rescore
  17. 2026-06-28 04:52 UTCEPSS rescore
  18. 2026-06-28 04:52 UTCEPSS rescore
  19. 2026-06-27 03:05 UTCEPSS rescore
  20. 2026-06-25 13:46 UTCEPSS rescore
  21. 2026-06-25 13:46 UTCEPSS rescore
  22. 2026-06-24 14:02 UTCEPSS rescore
  23. 2026-06-24 14:02 UTCEPSS rescore
  24. 2026-06-23 21:29 UTCEPSS rescore
  25. 2026-06-23 21:29 UTCEPSS rescore
  26. 2026-06-22 14:22 UTCEPSS rescore
  27. 2026-06-22 14:22 UTCEPSS rescore
  28. 2026-06-21 01:56 UTCEPSS rescore
  29. 2026-06-21 01:56 UTCEPSS rescore
  30. 2026-06-19 19:22 UTCEPSS rescore
  31. 2026-06-19 19:22 UTCEPSS rescore
  32. 2026-06-18 17:49 UTCEPSS rescore
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  34. 2026-06-17 17:49 UTCEPSS rescore
  35. 2026-06-17 17:49 UTCEPSS rescore
  36. 2026-06-16 17:49 UTCEPSS rescore
  37. 2026-06-16 17:49 UTCEPSS rescore
  38. 2026-06-15 17:44 UTCEPSS rescore
  39. 2026-06-13 22:57 UTCEPSS rescore
  40. 2026-06-12 23:08 UTCEPSS rescore
  41. 2026-06-12 23:08 UTCEPSS rescore
  42. 2026-06-10 22:14 UTCEPSS rescore
  43. 2026-06-10 13:17 UTCEPSS rescore
  44. 2026-06-08 14:13 UTCEPSS rescore
  45. 2026-06-07 15:22 UTCEPSS rescore
  46. 2026-06-07 15:22 UTCEPSS rescore
  47. 2026-06-06 13:44 UTCEPSS rescore
  48. 2026-06-06 13:44 UTCEPSS rescore
  49. 2026-06-06 13:44 UTCEPSS rescore
  50. 2026-06-05 22:44 UTCEPSS rescore
  51. 2026-06-05 22:44 UTCEPSS rescore
  52. 2026-06-05 06:07 UTCEPSS rescore
  53. 2026-06-04 13:09 UTCEPSS rescore
  54. 2026-06-04 13:09 UTCEPSS rescore
  55. 2026-06-02 20:10 UTCEPSS rescore
  56. 2026-06-02 20:10 UTCEPSS rescore
  57. 2026-06-01 13:49 UTCEPSS rescore
  58. 2026-06-01 13:49 UTCEPSS rescore
  59. 2026-05-31 22:28 UTCEPSS rescore
  60. 2026-05-31 22:28 UTCEPSS rescore
  61. 2026-05-31 00:13 UTCEPSS rescore
  62. 2026-05-31 00:13 UTCEPSS rescore
  63. 2026-05-30 14:25 UTCEG score recompute
  64. 2026-05-30 14:25 UTCVendor advisory
  65. 2026-05-30 14:25 UTCGHSA enrichment
  66. 2026-05-29 13:40 UTCEPSS rescore
  67. 2026-05-28 13:42 UTCEPSS rescore
  68. 2026-05-28 13:42 UTCEPSS rescore
  69. 2026-05-28 13:42 UTCEPSS rescore
  70. 2026-05-27 13:38 UTCEPSS rescore
  71. 2026-05-27 13:38 UTCEPSS rescore
  72. 2026-05-26 13:41 UTCEPSS rescore
  73. 2026-05-26 13:41 UTCEPSS rescore
  74. 2026-05-26 07:16 UTCEPSS rescore
  75. 2026-05-26 07:16 UTCEPSS rescore

Frequently asked(4)

What is CVE-2009-4020?
CVE-2009-4020 is a high vulnerability published on December 4, 2009. Stack-based buffer overflow in the hfs subsystem in the Linux kernel 2.6.32 allows remote attackers to have an unspecified impact via a crafted Hierarchical File System (HFS) filesystem, related to the hfs_readdir function in fs/hfs/dir.c.
When was CVE-2009-4020 disclosed?
CVE-2009-4020 was first published in the National Vulnerability Database on December 4, 2009, with the most recent update on April 23, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2009-4020 actively exploited?
CVE-2009-4020 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 5% probability of exploitation in the next 30 days, which ranks it in the top 8.5% of all scored CVEs.
How do I remediate CVE-2009-4020?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2009-4020, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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