CVE-2009-4016

MEDIUMCVSS v2 · 6.86.8—
EchelonGraph scoreLOW confidence

This CVE was only ever scored under CVSS v2.0. NVD CVSS v2.0 base 6.8 — v2 rates that MEDIUM (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:M/Au:N/C:P/I:P/A:P. 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 4.0% 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
6.8EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 4%CVSS v2: 6.8Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Integer underflow in the clean_string function in irc_string.c in (1) IRCD-hybrid 7.2.2 and 7.2.3, (2) ircd-ratbox before 2.2.9, and (3) oftc-hybrid before 1.6.8, when flatten_links is disabled, allows remote attackers to execute arbitrary code or cause a denial of service (daemon crash) via a LINKS command.

CVSS v2.0 (legacy)
6.8MEDIUMNVD never assigned a CVSS v3 rating to this CVE
EG Score
6.8(low)
EG Risk
37(Track)
EG Risk 37/100SSVC: 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
Severity68% × 45%
Exploitation4% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
4%
EPSS %ILE
90%
KEV
Not listed

Published

February 4, 2010

Last Modified

April 29, 2026

References (20)

Affected Packages

(6 across 5 ecosystems)
Debian:5.0(2)
PackageVulnerable rangeFixed inDependents
ircd-hybrid1:7.2.2.dfsg.2-41:7.2.2.dfsg.2-4+lenny1—
ircd-ratbox2.2.8.dfsg-22.2.8.dfsg-2+lenny1—
Debian:11(1)
PackageVulnerable rangeFixed inDependents
ircd-hybrid—1:7.2.2.dfsg.2-6.1—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
ircd-hybrid—1:7.2.2.dfsg.2-6.1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
ircd-hybrid—1:7.2.2.dfsg.2-6.1—
Debian:4.0(1)
PackageVulnerable rangeFixed inDependents
ircd-hybrid1:7.2.2.dfsg.2-31:7.2.2.dfsg.2-3+etch1—

Data Freshness Timeline

(refreshed 3× in last 7d / 12× 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 109 total refreshes for this CVE.

  1. 2026-08-27 14:19 UTCEPSS rescore
  2. 2026-08-25 13:43 UTCEPSS rescore
  3. 2026-08-24 22:05 UTCOSV refresh
  4. 2026-08-19 16:58 UTCEPSS rescore
  5. 2026-08-15 01:24 UTCEPSS rescore
  6. 2026-08-09 13:41 UTCEPSS rescore
  7. 2026-08-08 16:31 UTCEPSS rescore
  8. 2026-08-08 15:49 UTCOSV refresh
  9. 2026-08-06 13:41 UTCEPSS rescore
  10. 2026-08-03 10:28 UTCEPSS rescore
  11. 2026-07-30 16:22 UTCEPSS rescore
  12. 2026-07-30 01:26 UTCEPSS rescore
  13. 2026-07-26 13:39 UTCEG score recompute▲ 6.80
  14. 2026-07-25 14:12 UTCEPSS rescore
  15. 2026-07-24 14:12 UTCEPSS rescore
  16. 2026-07-23 14:14 UTCEPSS rescore
  17. 2026-07-23 08:49 UTCOSV refresh
  18. 2026-07-23 01:00 UTCEG score recompute
  19. 2026-07-23 00:37 UTCEG score recompute
  20. 2026-07-23 00:04 UTCEG score recompute
  21. 2026-07-22 21:43 UTCEG score recompute
  22. 2026-07-22 14:03 UTCEPSS rescore
  23. 2026-07-21 15:20 UTCEPSS rescore
  24. 2026-07-20 17:03 UTCEPSS rescore
  25. 2026-07-20 17:03 UTCEPSS rescore
Show 75 more
  1. 2026-07-18 09:59 UTCEPSS rescore
  2. 2026-07-16 16:58 UTCEPSS rescore
  3. 2026-07-15 16:54 UTCEPSS rescore
  4. 2026-07-15 16:54 UTCEPSS rescore
  5. 2026-07-15 01:55 UTCEPSS rescore
  6. 2026-07-13 22:25 UTCEPSS rescore
  7. 2026-07-13 06:07 UTCEPSS rescore
  8. 2026-07-11 08:22 UTCEPSS rescore
  9. 2026-07-11 08:22 UTCEPSS rescore
  10. 2026-07-09 19:04 UTCEPSS rescore
  11. 2026-07-08 15:10 UTCEPSS rescore
  12. 2026-07-06 16:23 UTCEPSS rescore
  13. 2026-07-06 03:32 UTCOSV refresh
  14. 2026-07-06 02:19 UTCEPSS rescore
  15. 2026-07-06 02:19 UTCEPSS rescore
  16. 2026-07-05 02:26 UTCEPSS rescore
  17. 2026-07-05 02:26 UTCEPSS rescore
  18. 2026-07-04 06:27 UTCEPSS rescore
  19. 2026-07-01 15:02 UTCEPSS rescore
  20. 2026-06-30 23:19 UTCEPSS rescore
  21. 2026-06-28 04:52 UTCEPSS rescore
  22. 2026-06-28 04:52 UTCEPSS rescore
  23. 2026-06-27 03:05 UTCEPSS rescore
  24. 2026-06-25 13:46 UTCEPSS rescore
  25. 2026-06-25 13:46 UTCEPSS rescore
  26. 2026-06-24 14:02 UTCEPSS rescore
  27. 2026-06-24 14:02 UTCEPSS rescore
  28. 2026-06-23 21:29 UTCEPSS rescore
  29. 2026-06-23 21:29 UTCEPSS rescore
  30. 2026-06-21 14:53 UTCEPSS rescore
  31. 2026-06-21 01:56 UTCEPSS rescore
  32. 2026-06-21 01:56 UTCEPSS rescore
  33. 2026-06-18 17:49 UTCEPSS rescore
  34. 2026-06-18 17:49 UTCEPSS rescore
  35. 2026-06-17 17:49 UTCEPSS rescore
  36. 2026-06-17 17:49 UTCEPSS rescore
  37. 2026-06-17 14:44 UTCOSV refresh
  38. 2026-06-16 17:49 UTCEPSS rescore
  39. 2026-06-16 17:49 UTCEPSS rescore
  40. 2026-06-15 17:44 UTCEPSS rescore
  41. 2026-06-14 23:14 UTCEPSS rescore
  42. 2026-06-14 23:14 UTCEPSS rescore
  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. 2026-05-29 13:40 UTCEPSS rescore
  68. 2026-05-29 12:54 UTCEG score recompute
  69. 2026-05-29 12:54 UTCGHSA enrichment
  70. 2026-05-28 13:42 UTCEPSS rescore
  71. 2026-05-28 13:42 UTCEPSS rescore
  72. 2026-05-28 13:42 UTCEPSS rescore
  73. 2026-05-27 13:38 UTCEPSS rescore
  74. 2026-05-27 13:38 UTCEPSS rescore
  75. 2026-05-26 13:41 UTCEPSS rescore

Frequently asked(4)

What is CVE-2009-4016?
CVE-2009-4016 is a medium vulnerability published on February 4, 2010. Integer underflow in the cleanstring function in ircstring.c in (1) IRCD-hybrid 7.2.2 and 7.2.3, (2) ircd-ratbox before 2.2.9, and (3) oftc-hybrid before 1.6.8, when flatten_links is disabled, allows remote attackers to execute arbitrary code or cause a denial of service (daemon crash) via a LINKS…
When was CVE-2009-4016 disclosed?
CVE-2009-4016 was first published in the National Vulnerability Database on February 4, 2010, with the most recent update on April 29, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2009-4016 actively exploited?
CVE-2009-4016 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 4% probability of exploitation in the next 30 days, which ranks it in the top 10.2% of all scored CVEs.
How do I remediate CVE-2009-4016?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2009-4016, 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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