CVE-2009-1891

HIGHCVSS v2 · 7.17.1—
EchelonGraph scoreLOW confidence

This CVE was only ever scored under CVSS v2.0. NVD CVSS v2.0 base 7.1 — 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:M/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 17.1% 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
Elevated
7.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 17%CVSS v2: 7.1Exploit: Elevated riskExposed: 0

A fix is available — apply it.

The mod_deflate module in Apache httpd 2.2.11 and earlier compresses large files until completion even after the associated network connection is closed, which allows remote attackers to cause a denial of service (CPU consumption).

CVSS v2.0 (legacy)
7.1HIGHNVD never assigned a CVSS v3 rating to this CVE
EG Score
7.1(low)
EG Risk
52(Track)
EG Risk 52/100SSVC: 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
Severity71% × 45%
Exploitation40% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
17%
EPSS %ILE
97%
KEV
Not listed

Published

July 10, 2009

Last Modified

April 23, 2026

References (110)

Vendor Advisories for CVE-2009-1891(2)

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

Patch Availability(7)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntuapache2-common (2.0.55-4ubuntu2.6) @ dapper2026-05-30ubuntu
redhatxml-commons-0:1.3.02-2jpp_1rh2010-08-04redhat
redhathttpd-0:2.0.52-41.ent.62009-11-11redhat
redhathttpd-0:2.0.46-75.ent2009-08-10redhat
redhathttpd22-0:2.2.10-23.1.ep5.el42009-07-17redhat
redhathttpd-0:2.2.10-10.ep5.el52009-07-14redhat
redhathttpd-0:2.2.3-22.el5_3.22009-07-09redhat

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

(6 across 6 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
apache2—2.2.11-7—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
apache2—2.2.11-7—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
apache2—2.2.11-7—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
apache2—2.2.11-7—
Debian:4.0(1)
PackageVulnerable rangeFixed inDependents
apache22.2.3-4 ... 2.2.3-4+etch8 (8 versions)2.2.3-4+etch9—
Debian:5.0(1)
PackageVulnerable rangeFixed inDependents
apache22.2.9-10+lenny2, 2.2.9-10+lenny32.2.9-10+lenny4—

Weakness Classification(1)

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

Additional Vendor Advisories

(5)

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 107 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 21:39 UTCOSV refresh
  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 13:38 UTCEG score recompute▲ 7.10
  11. 2026-07-25 14:12 UTCEPSS rescore
  12. 2026-07-24 22:11 UTCOSV refresh
  13. 2026-07-24 14:12 UTCEPSS rescore
  14. 2026-07-23 14:14 UTCEPSS rescore
  15. 2026-07-23 00:59 UTCEG score recompute
  16. 2026-07-23 00:37 UTCEG score recompute
  17. 2026-07-23 00:03 UTCEG score recompute
  18. 2026-07-22 21:42 UTCEG score recompute
  19. 2026-07-22 14:03 UTCEPSS rescore
  20. 2026-07-21 15:20 UTCEPSS rescore
  21. 2026-07-20 17:03 UTCEPSS rescore
  22. 2026-07-20 17:03 UTCEPSS rescore
  23. 2026-07-18 09:59 UTCEPSS rescore
  24. 2026-07-16 16:58 UTCEPSS rescore
  25. 2026-07-15 16:54 UTCEPSS rescore
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  1. 2026-07-15 16:54 UTCEPSS rescore
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  3. 2026-07-13 22:25 UTCEPSS rescore
  4. 2026-07-13 06:07 UTCEPSS rescore
  5. 2026-07-11 08:22 UTCEPSS rescore
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  7. 2026-07-09 19:04 UTCEPSS rescore
  8. 2026-07-08 15:10 UTCEPSS rescore
  9. 2026-07-07 17:12 UTCOSV refresh
  10. 2026-07-06 16:23 UTCEPSS rescore
  11. 2026-07-05 02:26 UTCEPSS rescore
  12. 2026-07-05 02:26 UTCEPSS rescore
  13. 2026-07-01 15:02 UTCEPSS rescore
  14. 2026-06-30 23:19 UTCEPSS rescore
  15. 2026-06-28 14:03 UTCEPSS rescore
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  18. 2026-06-27 03:05 UTCEPSS rescore
  19. 2026-06-25 13:46 UTCEPSS rescore
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  21. 2026-06-24 14:02 UTCEPSS rescore
  22. 2026-06-24 14:02 UTCEPSS rescore
  23. 2026-06-23 21:29 UTCEPSS rescore
  24. 2026-06-23 21:29 UTCEPSS rescore
  25. 2026-06-21 14:53 UTCEPSS rescore
  26. 2026-06-21 01:56 UTCEPSS rescore
  27. 2026-06-21 01:56 UTCEPSS rescore
  28. 2026-06-19 19:22 UTCEPSS rescore
  29. 2026-06-19 19:22 UTCEPSS rescore
  30. 2026-06-19 04:43 UTCOSV refresh
  31. 2026-06-18 17:49 UTCEPSS rescore
  32. 2026-06-18 17:49 UTCEPSS rescore
  33. 2026-06-17 17:49 UTCEPSS rescore
  34. 2026-06-17 17:49 UTCEPSS rescore
  35. 2026-06-16 17:49 UTCEPSS rescore
  36. 2026-06-16 17:49 UTCEPSS rescore
  37. 2026-06-15 17:44 UTCEPSS rescore
  38. 2026-06-14 23:14 UTCEPSS rescore
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  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 16:12 UTCEG score recompute
  64. 2026-05-30 16:12 UTCVendor advisory
  65. 2026-05-30 16:12 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. 2026-05-27 08:14 UTCOSV refresh
  73. 2026-05-26 07:16 UTCEPSS rescore
  74. 2026-05-26 07:16 UTCEPSS rescore
  75. 2026-05-24 16:43 UTCEPSS rescore

Frequently asked(4)

What is CVE-2009-1891?
CVE-2009-1891 is a high vulnerability published on July 10, 2009. The mod_deflate module in Apache httpd 2.2.11 and earlier compresses large files until completion even after the associated network connection is closed, which allows remote attackers to cause a denial of service (CPU consumption).
When was CVE-2009-1891 disclosed?
CVE-2009-1891 was first published in the National Vulnerability Database on July 10, 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-2009-1891 actively exploited?
CVE-2009-1891 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 17% probability of exploitation in the next 30 days, which ranks it in the top 3.2% of all scored CVEs.
How do I remediate CVE-2009-1891?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2009-1891, 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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