CVE-2009-3621

MEDIUMNVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

Score 5.5 from GitHub Security Advisory published 2022-05-02. NVD baseline CVSS 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Weaponized
5.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 5.5Exploit: Exploit-DB (verified) · public exploitExposed: 0

A fix is available — apply it.

net/unix/af_unix.c in the Linux kernel 2.6.31.4 and earlier allows local users to cause a denial of service (system hang) by creating an abstract-namespace AF_UNIX listening socket, performing a shutdown operation on this socket, and then performing a series of connect operations to this socket.

CVSS v3
5.5
EG Score
5.5(medium)
EG Risk
55(Track)
EG Risk 55/100SSVC: 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
Severity55% × 45%
Exploitation65% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
60%
KEV
Not listed

Published

October 22, 2009

Last Modified

April 23, 2026

References (52)

Vendor Advisories for CVE-2009-3621(2)

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

Patch Availability(4)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulinux-image-2.6.31-16-powerpc (2.6.31-16.52) @ karmic2026-05-30ubuntu
redhatkernel-0:2.6.9-89.0.18.EL2009-12-15redhat
redhatkernel-0:2.6.18-164.9.1.el52009-12-15redhat
redhatkernel-rt-0:2.6.24.7-137.el5rt2009-11-03redhat

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

(3 across 2 ecosystems)
Debian:4.0(2)
PackageVulnerable rangeFixed inDependents
linux-2.62.6.18.dfsg.1-12 ... 2.6.18.dfsg.1-26 (37 versions)2.6.18.dfsg.1-26etch1—
linux-2.6.242.6.24-5~etchnhalf.1 ... 2.6.24-6~etchnhalf.9 (13 versions)2.6.24-6~etchnhalf.9etch1—
Debian:5.0(1)
PackageVulnerable rangeFixed inDependents
linux-2.62.6.26-13 ... 2.6.26-19~bpo40+1 (20 versions)2.6.26-19lenny2—

Weakness Classification(1)

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

Additional Vendor Advisories

(2)

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 112 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
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  11. 2026-07-24 14:12 UTCEPSS rescore
  12. 2026-07-23 14:14 UTCEPSS rescore
  13. 2026-07-23 01:00 UTCEG score recompute
  14. 2026-07-23 00:37 UTCEG score recompute
  15. 2026-07-23 00:04 UTCEG score recompute
  16. 2026-07-22 21:43 UTCEG score recompute
  17. 2026-07-22 14:03 UTCEPSS rescore
  18. 2026-07-21 15:20 UTCEPSS rescore
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  21. 2026-07-18 09:59 UTCEPSS rescore
  22. 2026-07-16 16:58 UTCEPSS rescore
  23. 2026-07-15 16:54 UTCEPSS rescore
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  25. 2026-07-15 01:55 UTCEPSS rescore
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  1. 2026-07-13 22:25 UTCEPSS rescore
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  3. 2026-07-11 08:22 UTCEPSS rescore
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  5. 2026-07-09 19:04 UTCEPSS rescore
  6. 2026-07-08 15:10 UTCEPSS rescore
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  8. 2026-07-06 02:19 UTCEPSS rescore
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  10. 2026-07-05 02:26 UTCEPSS rescore
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  13. 2026-07-01 15:02 UTCEPSS rescore
  14. 2026-06-30 23:19 UTCEPSS rescore
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  18. 2026-06-28 04:52 UTCEPSS rescore
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  20. 2026-06-27 03:05 UTCEPSS rescore
  21. 2026-06-25 13:46 UTCEPSS rescore
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  23. 2026-06-24 14:02 UTCEPSS rescore
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  25. 2026-06-23 21:29 UTCEPSS rescore
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  27. 2026-06-22 14:22 UTCEPSS rescore
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  29. 2026-06-21 14:53 UTCEPSS rescore
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  40. 2026-06-15 17:44 UTCEPSS rescore
  41. 2026-06-14 23:14 UTCEPSS rescore
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  43. 2026-06-13 22:57 UTCEPSS rescore
  44. 2026-06-12 23:08 UTCEPSS rescore
  45. 2026-06-12 23:08 UTCEPSS rescore
  46. 2026-06-10 22:14 UTCEPSS rescore
  47. 2026-06-10 13:17 UTCEPSS rescore
  48. 2026-06-08 14:13 UTCEPSS rescore
  49. 2026-06-07 15:22 UTCEPSS rescore
  50. 2026-06-07 15:22 UTCEPSS rescore
  51. 2026-06-06 13:44 UTCEPSS rescore
  52. 2026-06-06 13:44 UTCEPSS rescore
  53. 2026-06-06 13:44 UTCEPSS rescore
  54. 2026-06-05 22:44 UTCEPSS rescore
  55. 2026-06-05 22:44 UTCEPSS rescore
  56. 2026-06-05 06:07 UTCEPSS rescore
  57. 2026-06-04 13:09 UTCEPSS rescore
  58. 2026-06-04 13:09 UTCEPSS rescore
  59. 2026-06-02 20:10 UTCEPSS rescore
  60. 2026-06-02 20:10 UTCEPSS rescore
  61. 2026-06-01 13:49 UTCEPSS rescore
  62. 2026-06-01 13:49 UTCEPSS rescore
  63. 2026-05-31 22:28 UTCEPSS rescore
  64. 2026-05-31 22:28 UTCEPSS rescore
  65. 2026-05-31 00:13 UTCEPSS rescore
  66. 2026-05-31 00:13 UTCEPSS rescore
  67. 2026-05-30 14:51 UTCEG score recompute
  68. 2026-05-30 14:51 UTCVendor advisory
  69. 2026-05-30 14:51 UTCGHSA enrichment
  70. 2026-05-29 13:40 UTCEPSS rescore
  71. 2026-05-28 13:42 UTCEPSS rescore
  72. 2026-05-28 13:42 UTCEPSS rescore
  73. 2026-05-28 13:42 UTCEPSS rescore
  74. 2026-05-27 13:38 UTCEPSS rescore
  75. 2026-05-27 13:38 UTCEPSS rescore

Publicly available exploits

(1 reference)

Working exploit code is in the public domain (1 Exploit-DB entry). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • Exploit-DBEDB-10022✓ verified
    First seen Nov 10, 2009

    Linux Kernel 2.6.31.4 - 'unix_stream_connect()' Local Denial of Service

    Open source ↗

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2009-3621?
CVE-2009-3621 is a medium vulnerability published on October 22, 2009. net/unix/afunix.c in the Linux kernel 2.6.31.4 and earlier allows local users to cause a denial of service (system hang) by creating an abstract-namespace AFUNIX listening socket, performing a shutdown operation on this socket, and then performing a series of connect operations to this socket.
When was CVE-2009-3621 disclosed?
CVE-2009-3621 was first published in the National Vulnerability Database on October 22, 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-2009-3621 actively exploited?
CVE-2009-3621 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 40.2% of all scored CVEs.
What is the CVSS score of CVE-2009-3621?
CVE-2009-3621 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2009-3621?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2009-3621, 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.

Dependency Blast Radius

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