lxml: javascript: URL bypass in Cleaner via xlink:href (lxml lxml)
At a glance
- Source
- NVD
- EPSS
- EPSS 0.30 % · percentile 22 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- GitHub_M
- NVD status
- Awaiting Analysis
Description
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.
Weaknesses (CWE)
- CWE-79 — Improper Neutralization of Input During Web Page Generation
- CWE-184 — Incomplete List of Disallowed Inputs
References
- https://github.com/fedora-python/lxml_html_clean/security/advisories/GHSA-4jhm-jv67-739f
- https://github.com/fedora-python/lxml_html_clean/commit/322357ac61c6cf80fcbaba53b4e92e31f3ded9f2
- https://github.com/lxml/lxml/commit/5927a6d5e851845140975d99b65461e255caaab0
- https://github.com/fedora-python/lxml_html_clean/releases/tag/0.4.5
- https://github.com/lxml/lxml/releases/tag/lxml-6.1.1
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | HIGH 8.2 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N | GitHub_M |
| CVSS 3.1 | HIGH 8.2 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N | NVD · security-advisories@github.com (Secondary) |
Advisories
- GHSA-4jhm-jv67-739f — `lxml_html_clean.Cleaner` does not strip `javascript:` URLs from namespaced URL attributes
- PYSEC-2026-2614 — `lxml_html_clean.Cleaner` does not strip `javascript:` URLs from namespaced URL attributes
European references
- ENISA EUVD · EUVD-2026-63390
- GCVE · GCVE-0-2026-49825
CERT-FR advisories
- CERTFR-2026-AVI-1336 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
Affected products
| Product | Versions |
|---|---|
| lxml · lxml | affected < 6.1.1 |
| fedora-python · lxml_html_clean | affected < 0.4.5 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |