Medium 6.1Published Mar 5, 2026

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

Updated under an hour ago (Oct 26, 2026, 3:00 AM ET)

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It affects fedora-python lxml_html_clean and 1 other product. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for fedora-python lxml_html_clean

Exploited in the last 30 days

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.

CVSS: 6.1 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Weakness (CWE): CWE-116
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Analyzed
Record last updated: Mar 6, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

fedora-python lxml_html_clean fedora_python:lxml_html_clean (from the name)	before 0.4.4	CNA record
fedoralovespython lxml_html_clean fedoralovespython:lxml_html_clean	before 0.4.4	NVD

References

https://github.com/fedora-python/lxml_html_clean/security/advisories/GHSA-hw26-mmpg-fqfgx-refsource-confirm, exploit, vendor-advisory
https://github.com/fedora-python/lxml_html_clean/commit/2ef732667ddbc74ea59847bcf24b75809aaeed3bx-refsource-misc, patch

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.