CVE-2026-49825 PUBLISHED

lxml: javascript: URL bypass in Cleaner via xlink:href

Assigner: GitHub_M
Reserved: 01.06.2026 Published: 20.08.2026 Updated: 20.08.2026

lxml is a library for processing XML and HTML in the Python language. Prior to 6.1.1, link attributes in lxml.html.defs.link_attrs were missing xlink:href, which can be used for URL bypass attacks in embedded SVG/MathML/etc. content. This vulnerability was fixed in lxml 6.1.1 and lxml_html_clean 0.4.5.

Metrics

CVSS 3.1

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N
CVSS Score: 8.2

Attack Vector	Network	Scope	Changed
Attack Complexity	Low	Confidentiality Impact	High
Privileges Required	None	Integrity Impact	Low
User Interaction	Required	Availability Impact	None

CVSS 3.1

Product Status

Vendor	lxml
Product	lxml
Versions	Version < 6.1.1 is affected

Vendor	fedora-python
Product	lxml_html_clean
Versions	Version < 0.4.5 is affected

References

Problem Types

CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') CWE
CWE-184: Incomplete List of Disallowed Inputs CWE