CVE-2026-28348
lxml-html-clean has CSS @import Filter Bypass via Unicode Escapes
6.1
MEDIUM
CVSS 3.1
EPSS 0.05%
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.
How to fix CVE-2026-28348
To remediate CVE-2026-28348, upgrade the affected package to a fixed version below.
- —no fix listed
- —upgrade to 0.4.4 or later
Is CVE-2026-28348 being exploited?
Low — EPSS is 0.1%, meaning exploitation activity has not been observed at scale.
Affected packages (2)
- from 0
- from 0, < 0.4.4
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM6.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N |