CVE-2009-3987

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:C/I:N/A:N. 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 1.6% exploitation probability in the next 30 days, which is reflected in EG Risk but does not lift the v2 base. Confidence: LOW.

Triggered by: NVD CVSS v2.0 (legacy fallback)
Sources: epss, nvd_v2
7.8EG
EchelonGraph verdictPlan mitigationSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1.6%CVSS v2: 7.8Exploit: None knownExposed 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).

The GeckoActiveXObject function in Mozilla Firefox before 3.0.16 and 3.5.x before 3.5.6, and SeaMonkey before 2.0.1, generates different exception messages depending on whether the referenced COM object is listed in the registry, which allows remote attackers to obtain potentially sensitive information about installed software by making multiple calls that specify the ProgID values of different COM objects.

CVSS v2.0 (legacy)
7.8HIGHNVD never assigned a CVSS v3 rating to this CVE
EG Score
7.8HIGHlow confidence
EG Risk
40
EG Risk 40/100CISA SSVC

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%
Exploitation2% × 40%
Automatability30% × 15%
CISA SSVC: Track at low or medium mission impact; Track or Track* or Attend at high (mission-essential systems).
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 or medium mission impact and sooner than that at high; until then, restrict network exposure of the affected system or apply the vendor's mitigation.
EPSS PROB
1.6%
EPSS %ILE
75th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Track or Track* or Attend at high (mission-essential systems).

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 or medium mission impact and sooner than that at high; until then, restrict network exposure of the affected system or apply the vendor's mitigation.

Exploitation none (no KEV listing, exploit record or EPSS ≥ 50%) · Automatable unknown (not published for this CVE) · Technical impact unknown (not published for this CVE). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

December 17, 2009

Last Modified

April 23, 2026

References (12)

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 7× in last 7d / 16× 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 80 of 108 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. 20 repeat rows among the latest 100 are merged into the row they repeat. The 28 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-10 19:54 UTCEPSS rescoreEPSS 1.6% · 75th percentile
  2. 2026-10-09 20:00 UTCEPSS rescoreEPSS 1.6% · 75th percentile
  3. 2026-10-08 16:33 UTCEPSS rescoreEPSS 1.6% · 75th percentile
  4. 2026-10-07 23:37 UTCEPSS rescoreEPSS 1.6% · 75th percentile
  5. 2026-10-06 15:09 UTCEPSS rescoreEPSS 1.6% · 75th percentile
  6. 2026-10-05 17:37 UTCEPSS rescoreEPSS 1.6% · 75th percentile
  7. 2026-10-04 23:15 UTCEPSS rescoreEPSS 1.6% · 75th percentile
  8. 2026-09-30 14:58 UTCEPSS rescoreEPSS 1.6% · 75th percentile
  9. 2026-09-29 08:01 UTCEG score recompute
  10. 2026-09-27 13:39 UTCEPSS rescoreEPSS 1.6% · 75th percentile
  11. 2026-09-26 15:52 UTCEPSS rescoreEPSS 1.6% · 75th percentile
  12. 2026-09-24 13:57 UTCEPSS rescoreEPSS 1.6% · 74th percentile
  13. 2026-09-17 19:20 UTCEPSS rescoreEPSS 1.6% · 74th percentile
  14. 2026-09-15 03:04 UTCEPSS rescoreEPSS 1.6% · 74th percentile
  15. 2026-09-13 16:40 UTCEPSS rescoreEPSS 1.6% · 74th percentile
  16. 2026-09-12 14:54 UTCEPSS rescoreEPSS 1.6% · 74th percentile
  17. 2026-09-10 09:24 UTCEPSS rescoreEPSS 1.6% · 74th percentile
  18. 2026-09-06 13:41 UTCEPSS rescoreEPSS 1.6% · 74th percentile
  19. 2026-09-05 15:22 UTCEPSS rescoreEPSS 1.6% · 74th percentile
  20. 2026-09-04 13:55 UTCEPSS rescoreEPSS 1.6% · 74th percentile
  21. 2026-08-28 21:34 UTCEPSS rescoreEPSS 1.6% · 73rd percentile
  22. 2026-08-27 14:19 UTCEPSS rescoreEPSS 1.6% · 74th percentile
  23. 2026-08-25 13:43 UTCEPSS rescoreEPSS 1.6% · 74th percentile
  24. 2026-08-19 16:58 UTCEPSS rescoreEPSS 1.6% · 74th percentile
  25. 2026-08-15 01:24 UTCEPSS rescoreEPSS 1.6% · 73rd percentile
Show 55 more
  1. 2026-08-09 13:41 UTCEPSS rescoreEPSS 1.6% · 73rd percentile
  2. 2026-08-08 16:31 UTCEPSS rescoreEPSS 1.6% · 73rd percentile
  3. 2026-08-06 13:41 UTCEPSS rescoreEPSS 1.6% · 73rd percentile
  4. 2026-08-03 10:28 UTCEPSS rescoreEPSS 1.6% · 73rd percentile
  5. 2026-07-30 16:22 UTCEPSS rescoreEPSS 1.6% · 73rd percentile
  6. 2026-07-30 01:26 UTCEPSS rescoreEPSS 1.6% · 73rd percentile
  7. 2026-07-26 13:39 UTCEG score recompute▲ 7.80
  8. 2026-07-25 14:12 UTCEPSS rescoreEPSS 1.6% · 73rd percentile
  9. 2026-07-24 14:12 UTCEPSS rescoreEPSS 1.6% · 73rd percentile
  10. 2026-07-23 14:14 UTCEPSS rescoreEPSS 1.6% · 73rd percentile
  11. 2026-07-23 01:00 UTCEG score recompute
  12. 2026-07-23 00:37 UTCEG score recompute
  13. 2026-07-23 00:04 UTCEG score recompute
  14. 2026-07-22 21:43 UTCEG score recompute
  15. 2026-07-22 14:03 UTCEPSS rescoreEPSS 1.6% · 73rd percentile
  16. 2026-07-21 15:20 UTCEPSS rescoreEPSS 1.6% · 73rd percentile
  17. 2026-07-20 17:03 UTCEPSS rescoreEPSS 1.6% · 73rd percentile
  18. 2026-07-18 09:59 UTCEPSS rescoreEPSS 1.6% · 73rd percentile
  19. 2026-07-16 16:58 UTCEPSS rescoreEPSS 1.6% · 73rd percentile
  20. 2026-07-15 16:54 UTCEPSS rescoreEPSS 1.6% · 73rd percentile
  21. 2026-07-15 01:55 UTCEPSS rescoreEPSS 1.6% · 73rd percentile
  22. 2026-07-13 22:25 UTCEPSS rescoreEPSS 1.6% · 73rd percentile
  23. 2026-07-13 06:07 UTCEPSS rescoreEPSS 1.6% · 73rd percentile
  24. 2026-07-11 08:22 UTCEPSS rescoreEPSS 1.6% · 73rd percentile
  25. 2026-07-09 19:04 UTCEPSS rescoreEPSS 1.6% · 73rd percentile
  26. 2026-07-08 15:10 UTCEPSS rescoreEPSS 1.6% · 73rd percentile
  27. 2026-07-06 16:23 UTCEPSS rescoreEPSS 1.6% · 73rd percentile
  28. 2026-07-06 02:19 UTCEPSS rescoreEPSS 1.6% · 73rd percentile
  29. 2026-07-05 02:26 UTCEPSS rescoreEPSS 1.6% · 73rd percentile
  30. 2026-07-04 06:27 UTCEPSS rescoreEPSS 1.6% · 73rd percentile
  31. 2026-07-01 15:02 UTCEPSS rescoreEPSS 1.6% · 73rd percentile
  32. 2026-06-30 23:19 UTCEPSS rescoreEPSS 1.6% · 73rd percentile
  33. 2026-06-28 14:03 UTCEPSS rescoreEPSS 1.6% · 73rd percentile
  34. 2026-06-28 04:52 UTCEPSS rescoreEPSS 1.6% · 73rd percentile
  35. 2026-06-27 03:05 UTCEPSS rescoreEPSS 1.6% · 72nd percentile
  36. 2026-06-25 13:46 UTCEPSS rescoreEPSS 1.6% · 72nd percentile
  37. 2026-06-24 14:02 UTCEPSS rescoreEPSS 1.6% · 72nd percentile
  38. 2026-06-23 21:29 UTCEPSS rescoreEPSS 1.6% · 72nd percentile
  39. 2026-06-22 14:22 UTCEPSS rescoreEPSS 1.6% · 72nd percentile
  40. 2026-06-21 14:53 UTCEPSS rescoreEPSS 1.6% · 72nd percentile
  41. 2026-06-19 19:22 UTCEPSS rescoreEPSS 1.6% · 72nd percentile
  42. 2026-06-18 17:49 UTCEPSS rescoreEPSS 1.6% · 72nd percentile
  43. 2026-06-17 17:49 UTCEPSS rescoreEPSS 1.6% · 72nd percentile
  44. 2026-06-16 17:49 UTCEPSS rescoreEPSS 1.6% · 72nd percentile
  45. 2026-06-15 17:44 UTCEPSS rescoreEPSS 1.6% · 72nd percentile
  46. 2026-06-14 23:14 UTCEPSS rescoreEPSS 0.8% · 74th percentile
  47. 2026-06-13 22:57 UTCEPSS rescoreEPSS 0.8% · 74th percentile
  48. 2026-06-12 23:08 UTCEPSS rescoreEPSS 0.8% · 74th percentile
  49. 2026-06-10 22:14 UTCEPSS rescoreEPSS 0.8% · 74th percentile
  50. 2026-06-10 13:17 UTCEPSS rescoreEPSS 0.8% · 74th percentile
  51. 2026-06-08 14:13 UTCEPSS rescoreEPSS 0.8% · 74th percentile
  52. 2026-06-07 15:22 UTCEPSS rescoreEPSS 0.8% · 74th percentile
  53. 2026-06-06 13:44 UTCEPSS rescoreEPSS 0.8% · 74th percentile
  54. 2026-06-05 22:44 UTCEPSS rescoreEPSS 0.8% · 74th percentile
  55. 2026-06-05 06:07 UTCEPSS rescoreEPSS 0.8% · 74th percentile

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Frequently asked(4)

What is CVE-2009-3987?
CVE-2009-3987 is a high vulnerability published on December 17, 2009. The GeckoActiveXObject function in Mozilla Firefox before 3.0.16 and 3.5.x before 3.5.6, and SeaMonkey before 2.0.1, generates different exception messages depending on whether the referenced COM object is listed in the registry, which allows remote attackers to obtain potentially sensitive…
When was the CVE record for CVE-2009-3987 published?
The CVE record for CVE-2009-3987 was published on December 17, 2009. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of April 23, 2026; the record at its source may have been updated since.
Is CVE-2009-3987 actively exploited?
CVE-2009-3987 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.6% probability of exploitation in the next 30 days (75th percentile of EPSS-scored CVEs).
How do I remediate CVE-2009-3987?
A fix for CVE-2009-3987 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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