What is CVE-2026-49825?

CVE-2026-49825 is a high-severity vulnerability in Fedora-Python Lxml HTML Clean, classified under Cross-site Scripting. CVSS score: 8.2/10. Published 2026-08-20.

How severe is CVE-2026-49825?

High severity. CVSS v3 base score is 8.2 out of 10.

XSS in Fedora-Python Lxml HTML Clean

CVE-2026-49825

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.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2026-08-20 · last modified 2026-09-18.

CVSS v3 metric

CVSS v3 base score 8.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N.

EPSS exploit prediction

EPSS: 0.003 (20.3th percentile), scored 2026-10-05.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 20th percentile — 20.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.001

Affected products

Fedora-Python Lxml HTML Clean — versions < 0.4.5
Lxml — versions < 6.1.1

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-49825?: CVE-2026-49825 is a high-severity vulnerability in Fedora-Python Lxml HTML Clean, classified under Cross-site Scripting. CVSS score: 8.2/10. Published 2026-08-20.
How severe is CVE-2026-49825?: High severity. CVSS v3 base score is 8.2 out of 10.