CVE-2026-28348 MEDIUM

CVE-2026-28348: lxml_html_clean: CSS @import Filter Bypass via Unicode Escapes

Vendor Fedora-Python
Product lxml_html_clean
Weakness CWE-116
Published March 5, 2026
Last update March 6, 2026
View on NVD All CVEs

CVSS base score

6.1/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction Required
Confidentiality Low
Integrity Low

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

March 5, 2026 CVE published
March 6, 2026 Record updated