HTML Cleaning Functionality Flaw in lxml_html_clean by Fedora Python
CVE-2026-28348

6.1MEDIUM

Key Information:

Vendor

Fedora-python

Status
Lxml Html Clean
Vendor
CVE Published:
5 March 2026

What is CVE-2026-28348?

The lxml_html_clean project has a significant vulnerability related to its HTML cleaning functionalities. The _has_sneaky_javascript() method, prior to version 0.4.4, inadequately processes backslashes, which allows CSS Unicode escape sequences to evade crucial filters designed to block dangerous CSS keywords. This oversight can lead to the unauthorized loading of external CSS resources and the potential for cross-site scripting (XSS) attacks, especially in older browser versions. Users are advised to upgrade to version 0.4.4 to mitigate this issue.

Affected Version(s)

lxml_html_clean < 0.4.4

References

https://github.com/fedora-python/lxml_html_clean/security...
x_refsource_CONFIRM
https://github.com/fedora-python/lxml_html_clean/commit/2...
x_refsource_MISC

CVSS V3.1

Score:
6.1
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
Low
Availability:
Low
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
Required
Scope:
Changed

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.