CVE-2009-3720

MEDIUMCVSS v2 · 5.05.0—
EchelonGraph scoreLOW confidence

This CVE was only ever scored under CVSS v2.0. NVD CVSS v2.0 base 5.0 — 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:L/Au:N/C:N/I:N/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 27.9% 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
Elevated
5.0EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 28%CVSS v2: 5.0Exploit: Elevated riskExposed services: Not assessed

A fix is available — apply it.

The updatePosition function in lib/xmltok_impl.c in libexpat in Expat 2.0.1, as used in Python, PyXML, w3c-libwww, and other software, allows context-dependent attackers to cause a denial of service (application crash) via an XML document with crafted UTF-8 sequences that trigger a buffer over-read, a different vulnerability than CVE-2009-2625.

CVSS v2.0 (legacy)
5.0MEDIUMNVD never assigned a CVSS v3 rating to this CVE
EG Score
5.0MEDIUMlow confidence
EG Risk
43
EG Risk 43/100CISA 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
Severity50% × 45%
Exploitation40% × 40%
Automatability30% × 15%
CISA SSVC: Track at low, Track or Track* at medium and Track* or Attend at high mission impact.
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
28%
EPSS %ILE
98th
KEV
Not listed

CISA SSVCTrack at low, Track or Track* at medium and Track* or Attend at high mission impact.

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation public PoC (EG-KEV: elevated) · 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

November 3, 2009

Last Modified

July 20, 2026

References (186)

Vendor Advisories for CVE-2009-3720(4)

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

Patch Availability(13)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntupython2.5 (2.5.2-11.1ubuntu1.1) @ intrepid2026-05-30ubuntu
ubuntupython2.4 (2.4.6-1ubuntu3.2.9.10.1) @ karmic2026-05-30ubuntu
ubuntulibexpat1 (2.0.1-4ubuntu1.1) @ karmic2026-05-30ubuntu
ubuntucmake (2.6.2-1ubuntu1.1) @ jaunty2026-05-30ubuntu
ubuntupython2.4-xml (0.8.4-1ubuntu3.1) @ dapper2026-05-30ubuntu
ubuntulibxmlrpc-core-c3 (1.06.27-1ubuntu6.1) @ karmic2026-05-30ubuntu
redhatpatch2017-11-16redhat
redhatpatch2011-06-22redhat
redhatpython-0:2.4.3-44.el52011-05-05redhat
redhatpython-0:2.3.4-14.10.el42011-05-05redhat
redhatPyXML-0:0.8.4-4.el5_4.22010-01-04redhat
redhatexpat-0:1.95.8-8.3.el5_4.22009-12-07redhat
redhat4Suite-0:1.0-3.el4_8.12009-11-10redhat

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

(50 across 6 ecosystems)
Debian:11(12)
PackageVulnerable rangeFix by version rangeDependents
audacity—
  • every version up to 1.3.2-1: fixed in 1.3.2-1
—
cadaver0.23.3-2.1 ... 0.28+dfsg-2 (10 versions)
  • every version on: no fix on record
—
cmake—
  • every version up to 2.6.0-6: fixed in 2.6.0-6
—
coin3—
  • every version up to 4.0.0~CMake~6f54f1602475+ds1-1: fixed in 4.0.0~CMake~6f54f1602475+ds1-1
—
expat—
  • every version up to 2.0.1-5: fixed in 2.0.1-5
—
gdcm—
  • every version up to 2.0.14-2: fixed in 2.0.14-2
—
ghostscript—
  • every version up to 8.71~dfsg-2: fixed in 8.71~dfsg-2
—
libxmltok1.2-4, 1.2-4.1, 1.2-4.1~exp1, 1.2-4.2
  • every version on: no fix on record
—
matanza0.13+ds2-1, 0.13+ds2-2
  • every version on: no fix on record
—
mcabber—
  • every version up to 0.10.0-1: fixed in 0.10.0-1
—
paraview—
  • every version up to 3.6.2-1: fixed in 3.6.2-1
—
poco—
  • every version up to 1.3.6p1-1: fixed in 1.3.6p1-1
—
Debian:12(12)
PackageVulnerable rangeFix by version rangeDependents
audacity—
  • every version up to 1.3.2-1: fixed in 1.3.2-1
—
cadaver0.24+dfsg-1 ... 0.28+dfsg-2 (8 versions)
  • every version on: no fix on record
—
cmake—
  • every version up to 2.6.0-6: fixed in 2.6.0-6
—
coin3—
  • every version up to 4.0.0~CMake~6f54f1602475+ds1-1: fixed in 4.0.0~CMake~6f54f1602475+ds1-1
—
expat—
  • every version up to 2.0.1-5: fixed in 2.0.1-5
—
gdcm—
  • every version up to 2.0.14-2: fixed in 2.0.14-2
—
ghostscript—
  • every version up to 8.71~dfsg-2: fixed in 8.71~dfsg-2
—
libxmltok1.2-4, 1.2-4.1, 1.2-4.1~exp1, 1.2-4.2
  • every version on: no fix on record
—
matanza0.13+ds2-1, 0.13+ds2-2
  • every version on: no fix on record
—
mcabber—
  • every version up to 0.10.0-1: fixed in 0.10.0-1
—
paraview—
  • every version up to 3.6.2-1: fixed in 3.6.2-1
—
poco—
  • every version up to 1.3.6p1-1: fixed in 1.3.6p1-1
—
Debian:13(11)
PackageVulnerable rangeFix by version rangeDependents
audacity—
  • every version up to 1.3.2-1: fixed in 1.3.2-1
—
cadaver0.26+dfsg-2, 0.28+dfsg-1, 0.28+dfsg-2
  • every version on: no fix on record
—
cmake—
  • every version up to 2.6.0-6: fixed in 2.6.0-6
—
coin3—
  • every version up to 4.0.0~CMake~6f54f1602475+ds1-1: fixed in 4.0.0~CMake~6f54f1602475+ds1-1
—
expat—
  • every version up to 2.0.1-5: fixed in 2.0.1-5
—
gdcm—
  • every version up to 2.0.14-2: fixed in 2.0.14-2
—
ghostscript—
  • every version up to 8.71~dfsg-2: fixed in 8.71~dfsg-2
—
matanza0.13+ds2-2
  • every version on: no fix on record
—
mcabber—
  • every version up to 0.10.0-1: fixed in 0.10.0-1
—
paraview—
  • every version up to 3.6.2-1: fixed in 3.6.2-1
—
poco—
  • every version up to 1.3.6p1-1: fixed in 1.3.6p1-1
—
Debian:14(11)
PackageVulnerable rangeFix by version rangeDependents
audacity—
  • every version up to 1.3.2-1: fixed in 1.3.2-1
—
cadaver0.26+dfsg-2, 0.28+dfsg-1, 0.28+dfsg-2
  • every version on: no fix on record
—
cmake—
  • every version up to 2.6.0-6: fixed in 2.6.0-6
—
coin3—
  • every version up to 4.0.0~CMake~6f54f1602475+ds1-1: fixed in 4.0.0~CMake~6f54f1602475+ds1-1
—
expat—
  • every version up to 2.0.1-5: fixed in 2.0.1-5
—
gdcm—
  • every version up to 2.0.14-2: fixed in 2.0.14-2
—
ghostscript—
  • every version up to 8.71~dfsg-2: fixed in 8.71~dfsg-2
—
matanza0.13+ds2-2
  • every version on: no fix on record
—
mcabber—
  • every version up to 0.10.0-1: fixed in 0.10.0-1
—
paraview—
  • every version up to 3.6.2-1: fixed in 3.6.2-1
—
poco—
  • every version up to 1.3.6p1-1: fixed in 1.3.6p1-1
—
Debian:4.0(2)
PackageVulnerable rangeFix by version rangeDependents
expat1.95.8-3.4
  • every version up to 1.95.8-3.4+etch1: fixed in 1.95.8-3.4+etch1
—
python2.42.4.4-3, 2.4.4-3+etch1, 2.4.4-3+etch2
  • every version up to 2.4.4-3+etch3: fixed in 2.4.4-3+etch3
—
Debian:5.0(2)
PackageVulnerable rangeFix by version rangeDependents
expat2.0.1-4
  • every version up to 2.0.1-4+lenny1: fixed in 2.0.1-4+lenny1
—
python2.42.4.6-1
  • every version up to 2.4.6-1+lenny1: fixed in 2.4.6-1+lenny1
—

Additional Vendor Advisories

(9)

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 5× in last 7d / 17× 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 127 total refreshes for this CVE.

  1. 2026-10-09 20:00 UTCEPSS rescore
  2. 2026-10-08 16:33 UTCEPSS rescore
  3. 2026-10-07 23:37 UTCEPSS rescore
  4. 2026-10-06 15:09 UTCEPSS rescore
  5. 2026-10-05 17:37 UTCEPSS rescore
  6. 2026-10-03 04:09 UTCOSV refresh
  7. 2026-09-30 14:58 UTCEPSS rescore
  8. 2026-09-29 08:00 UTCEG score recompute
  9. 2026-09-27 13:39 UTCEPSS rescore
  10. 2026-09-26 15:52 UTCEPSS rescore
  11. 2026-09-24 13:57 UTCEPSS rescore
  12. 2026-09-17 19:20 UTCEPSS rescore
  13. 2026-09-15 03:04 UTCEPSS rescore
  14. 2026-09-14 01:20 UTCOSV refresh
  15. 2026-09-13 16:40 UTCEPSS rescore
  16. 2026-09-12 14:54 UTCEPSS rescore
  17. 2026-09-10 09:24 UTCEPSS rescore
  18. 2026-09-06 13:41 UTCEPSS rescore
  19. 2026-09-05 15:22 UTCEPSS rescore
  20. 2026-09-04 13:55 UTCEPSS rescore
  21. 2026-08-28 21:34 UTCEPSS rescore
  22. 2026-08-27 14:19 UTCEPSS rescore
  23. 2026-08-26 02:40 UTCOSV refresh
  24. 2026-08-25 13:43 UTCEPSS rescore
  25. 2026-08-19 16:58 UTCEPSS rescore
Show 75 more
  1. 2026-08-15 01:24 UTCEPSS rescore
  2. 2026-08-09 19:10 UTCOSV refresh
  3. 2026-08-08 16:31 UTCEPSS rescore
  4. 2026-08-06 13:41 UTCEPSS rescore
  5. 2026-07-30 16:22 UTCEPSS rescore
  6. 2026-07-26 13:39 UTCEG score recompute▲ 5.00
  7. 2026-07-25 14:12 UTCEPSS rescore
  8. 2026-07-24 20:11 UTCOSV refresh
  9. 2026-07-24 14:12 UTCEPSS rescore
  10. 2026-07-23 14:14 UTCEPSS rescore
  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 rescore
  16. 2026-07-21 15:20 UTCEPSS rescore
  17. 2026-07-20 17:03 UTCEPSS rescore
  18. 2026-07-20 17:03 UTCEPSS rescore
  19. 2026-07-18 09:59 UTCEPSS rescore
  20. 2026-07-16 16:58 UTCEPSS rescore
  21. 2026-07-15 16:54 UTCEPSS rescore
  22. 2026-07-15 16:54 UTCEPSS rescore
  23. 2026-07-15 01:55 UTCEPSS rescore
  24. 2026-07-13 22:25 UTCEPSS rescore
  25. 2026-07-13 06:07 UTCEPSS rescore
  26. 2026-07-11 08:22 UTCEPSS rescore
  27. 2026-07-11 08:22 UTCEPSS rescore
  28. 2026-07-09 19:04 UTCEPSS rescore
  29. 2026-07-08 15:10 UTCEPSS rescore
  30. 2026-07-07 15:11 UTCOSV refresh
  31. 2026-07-06 16:23 UTCEPSS rescore
  32. 2026-07-05 02:26 UTCEPSS rescore
  33. 2026-07-05 02:26 UTCEPSS rescore
  34. 2026-07-01 15:02 UTCEPSS rescore
  35. 2026-06-30 23:19 UTCEPSS rescore
  36. 2026-06-29 14:02 UTCEPSS rescore
  37. 2026-06-29 14:02 UTCEPSS rescore
  38. 2026-06-28 14:03 UTCEPSS rescore
  39. 2026-06-28 04:52 UTCEPSS rescore
  40. 2026-06-28 04:52 UTCEPSS rescore
  41. 2026-06-27 03:05 UTCEPSS rescore
  42. 2026-06-25 13:46 UTCEPSS rescore
  43. 2026-06-25 13:46 UTCEPSS rescore
  44. 2026-06-24 14:02 UTCEPSS rescore
  45. 2026-06-24 14:02 UTCEPSS rescore
  46. 2026-06-23 21:29 UTCEPSS rescore
  47. 2026-06-23 21:29 UTCEPSS rescore
  48. 2026-06-21 01:56 UTCEPSS rescore
  49. 2026-06-21 01:56 UTCEPSS rescore
  50. 2026-06-19 02:35 UTCOSV refresh
  51. 2026-06-18 17:49 UTCEPSS rescore
  52. 2026-06-18 17:49 UTCEPSS rescore
  53. 2026-06-17 17:49 UTCEPSS rescore
  54. 2026-06-17 17:49 UTCEPSS rescore
  55. 2026-06-16 17:49 UTCEPSS rescore
  56. 2026-06-16 17:49 UTCEPSS rescore
  57. 2026-06-15 17:44 UTCEPSS rescore
  58. 2026-06-14 23:14 UTCEPSS rescore
  59. 2026-06-14 23:14 UTCEPSS rescore
  60. 2026-06-13 22:57 UTCEPSS rescore
  61. 2026-06-12 23:08 UTCEPSS rescore
  62. 2026-06-12 23:08 UTCEPSS rescore
  63. 2026-06-10 22:14 UTCEPSS rescore
  64. 2026-06-10 13:17 UTCEPSS rescore
  65. 2026-06-08 14:13 UTCEPSS rescore
  66. 2026-06-07 15:22 UTCEPSS rescore
  67. 2026-06-07 15:22 UTCEPSS rescore
  68. 2026-06-05 22:44 UTCEPSS rescore
  69. 2026-06-05 22:44 UTCEPSS rescore
  70. 2026-06-05 06:07 UTCEPSS rescore
  71. 2026-06-04 13:09 UTCEPSS rescore
  72. 2026-06-04 13:09 UTCEPSS rescore
  73. 2026-06-02 20:10 UTCEPSS rescore
  74. 2026-06-02 20:10 UTCEPSS rescore
  75. 2026-06-01 13:49 UTCEPSS rescore

Related CVEs(same product + same vendor)

Frequently asked(4)

What is CVE-2009-3720?
CVE-2009-3720 is a medium vulnerability published on November 3, 2009. The updatePosition function in lib/xmltok_impl.c in libexpat in Expat 2.0.1, as used in Python, PyXML, w3c-libwww, and other software, allows context-dependent attackers to cause a denial of service (application crash) via an XML document with crafted UTF-8 sequences that trigger a buffer…
When was CVE-2009-3720 disclosed?
CVE-2009-3720 was first published on November 3, 2009, with the most recent update on July 20, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2009-3720 actively exploited?
CVE-2009-3720 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 28% probability of exploitation in the next 30 days (98th percentile of EPSS-scored CVEs).
How do I remediate CVE-2009-3720?
A fix for CVE-2009-3720 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2009-3720 are linked in the Vendor Advisories panel on this page.

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