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CVE-2021-43818


lxml is a library for processing XML and HTML in the Python language. Prior to version 4.6.5, the HTML Cleaner in lxml.html lets certain crafted script content pass through, as well as script content in SVG files embedded using data URIs. Users that employ the HTML cleaner in a security relevant context should upgrade to lxml 4.6.5 to receive a patch. There are no known workarounds available.


Security Impact Summary

This vulnerability carries a HIGH severity rating with a CVSS v3.1 score of 8.2, indicating it can be exploited remotely over the network with relatively low complexity though user interaction is required and does not require pre-existing privileges . The vulnerability impacts limited data confidentiality, integrity (unauthorized modifications), for affected systems. Impacting 12 products from lxml, from fedoraproject, from debian and 9 others, organizations running these solutions should prioritize assessment and patching.

Historical Context

Reported in 2021, this vulnerability emerged during an era marked by increased sophistication in supply chain attacks, cloud infrastructure vulnerabilities, and software-as-a-service (SaaS) security challenges. Security practices during this period emphasized zero-trust architectures, container security, and API protection.


Published

2021-12-13T18:15:08.387

Last Modified

2024-11-21T06:29:51.497

Status

Modified

Source

[email protected]

Severity

CVSSv3.1: 8.2 (HIGH)

CVSSv2 Vector

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

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

8.6

Impact Score

6.4

Weaknesses
  • Type: Secondary
    CWE-74
    CWE-79
  • Type: Primary
    CWE-79

Affected Vendors & Products
Type Vendor Product Version/Range Vulnerable?
Application lxml lxml < 4.6.5 Yes
Operating System fedoraproject fedora 34 Yes
Operating System fedoraproject fedora 35 Yes
Operating System debian debian_linux 9.0 Yes
Operating System debian debian_linux 10.0 Yes
Operating System debian debian_linux 11.0 Yes
Application netapp solidfire - Yes
Application netapp solidfire_enterprise_sds - Yes
Operating System netapp hci_storage_node_firmware - Yes
Hardware netapp hci_storage_node - No
Application oracle communications_cloud_native_core_binding_support_function 22.1.3 Yes
Application oracle communications_cloud_native_core_network_exposure_function 22.1.1 Yes
Application oracle communications_cloud_native_core_policy 22.2.0 Yes
Application oracle http_server 12.2.1.3.0 Yes
Application oracle http_server 12.2.1.4.0 Yes
Application oracle zfs_storage_appliance_kit 8.8 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 lxml'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.