CVE-2026-28348: lxml_html_clean is a project for HTML cleaning functionalities copied from `lxml.html.clean`

Routine

MEDIUM 6.1UPGRADE

CVE-2026-28348 is a medium-severity flaw (CVSS 6.1) affecting lxml html clean. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	6.1 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.2% (top 84%)
CISA exploited list	No
Weakness	CWE-116
Published	2026-03-05
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: fedoralovespython

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-03-05 20:16 UTCPublished CVE record published
2026-06-17 10:28 UTCUpdated Record last modified

fedoralovespython lxml html clean UPGRADE

Affected: < 0.4.4

Fixed in: 0.4.4

Safe to downgrade to: no unaffected older release

1. Check installed version

pip show lxml-html-clean

2. UPGRADE to 0.4.4

pip install --upgrade "lxml-html-clean>=0.4.4"

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-28348?

lxml html clean: upgrade to 0.4.4. Exact commands for each OS are on this page.

Is CVE-2026-28348 being exploited?

CVE-2026-28348 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-28348 affect?

CVE-2026-28348 affects lxml html clean. Severity is medium (CVSS 6.1). 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

How urgent is CVE-2026-28348?

Priority 30/100. Public exploit reference

Related CVEs

CVE-2026-28350 MEDIUM 6.1 UPGRADE lxml_html_clean is a project for HTML cleaning functionalities copied from `lxml.html.clean`
CVE-2024-52595 HIGH 7.7 UPGRADE lxml_html_clean is a project for HTML cleaning functionalities copied from `lxml.html.clean`

References

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