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6.1

Lxml_html_clean: CSS Loading or XSS in Older Browsers

UBUNTU-CVE-2026-28348
Summary

If you're using an older version of lxml_html_clean to clean HTML, attackers can load malicious CSS or cause cross-site scripting attacks in older browsers. Update to version 0.4.4 to fix this issue. If an update isn't possible, consider using a different HTML cleaning tool to ensure your website is secure.

What to do

No fix is available yet. Check with your software vendor for updates.

Affected software
VendorProductAffected versionsFix available
canonical lxml-html-clean All versions
canonical lxml-html-clean All versions
Original title
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 dang...
Original 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.
osv CVSS3.1 6.1
Published: 6 Mar 2026 · Updated: 13 Mar 2026 · First seen: 9 Mar 2026