lxml_html_clean: CSS @import Filter Bypass via Unicode Escapes (fedora-python lxml_html_clean)
At a glance
- Source
- NVD
- EPSS
- EPSS 0.28 % · percentile 21 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- GitHub_M
- NVD status
- Analyzed
Description
lxml_html_clean is a project for HTML cleaning functionalities copied from `lxml.html.clean`. Prior to version 0.4.4, the _has_sneaky_javascript() method strips backslashes before checking for dangerous CSS keywords. This causes CSS Unicode escape sequences to bypass the @import and expression() filters, allowing external CSS loading or XSS in older browsers. This issue has been patched in version 0.4.4.
Weaknesses (CWE)
- CWE-116 — Improper Encoding or Escaping of Output
References
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | MEDIUM 6.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N | GitHub_M |
| CVSS 3.1 | MEDIUM 6.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N | NVD · security-advisories@github.com (Secondary) |
Advisories
- GHSA-hw26-mmpg-fqfg — lxml-html-clean has CSS @import Filter Bypass via Unicode Escapes
- PYSEC-2026-2201 — lxml_html_clean is a project for HTML cleaning functionalities copied from `lxml.html.clean`. Prior to version 0.4.4, the _has_sneaky_javascript() method strips
European references
- ENISA EUVD · EUVD-2026-9868
- GCVE · GCVE-0-2026-28348
CERT-FR advisories
- CERTFR-2026-AVI-0648 — Multiples vulnérabilités dans Kaspersky Anti Targeted Attack Platform · cert.ssi.gouv.fr
Affected configurations (NVD CPE)
cpe:2.3:a:fedoralovespython:lxml_html_clean:*:*:*:*:*:python:*:*< 0.4.4
Affected products
| Product | Versions |
|---|---|
| fedora-python · lxml_html_clean | affected < 0.4.4 |
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 |