Vulnerability Monitor

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CVE-2009-3720


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.


Security Impact Summary

CVE-2009-3720 is a security vulnerability that . Impacting 4 products from libexpat_project, from a_m_kuchling, from python and 1 other, organizations running these solutions should prioritize assessment and patching.

Historical Context

Originally identified in 2009, this vulnerability predates many modern security frameworks and practices. The vulnerability landscape of that era was characterized by different threat models and less mature defense mechanisms compared to contemporary standards.


Published

2009-11-03T16:30:12.563

Last Modified

2025-04-09T00:30:58.490

Status

Deferred

Source

[email protected]

Severity

CVSSv2: 5.0 (MEDIUM)

CVSSv2 Vector

AV:N/AC:L/Au:N/C:N/I:N/A:P

  • Access Vector: NETWORK
  • Access Complexity: LOW
  • Authentication: NONE
  • Confidentiality Impact: NONE
  • Integrity Impact: NONE
  • Availability Impact: PARTIAL
Exploitability Score

10.0

Impact Score

2.9

Weaknesses
  • Type: Primary
    NVD-CWE-noinfo

Affected Vendors & Products
Type Vendor Product Version/Range Vulnerable?
Application libexpat_project libexpat 2.0.1 Yes
Application a_m_kuchling pyxml * No
Application python python * No
Application apache http_server < 2.0.64 Yes
Application apache http_server < 2.2.17 Yes

References

How SecUtils Interprets This CVE

SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For libexpat_project's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.