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6.1
lxml_html_clean: Unpatched <base> tag lets attackers hijack links
UBUNTU-CVE-2026-28350
Summary
An attacker can inject a <base> tag into a web page and hijack relative links. This happened because the lxml_html_clean library didn't properly handle the <base> tag until version 0.4.4. Update to version 0.4.4 or later to fix the issue.
What to do
No fix is available yet. Check with your software vendor for updates.
Affected software
| Vendor | Product | Affected versions | Fix 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 <base> tag passes through the default Cleaner configuration. While page_str...
Original description
lxml_html_clean is a project for HTML cleaning functionalities copied from `lxml.html.clean`. Prior to version 0.4.4, the <base> tag passes through the default Cleaner configuration. While page_structure=True removes html, head, and title tags, there is no specific handling for <base>, allowing an attacker to inject it and hijack relative links on the page. This issue has been patched in version 0.4.4.
osv CVSS3.1
6.1
- https://ubuntu.com/security/CVE-2026-28350 Third Party Advisory
- https://www.cve.org/CVERecord?id=CVE-2026-28350 Third Party Advisory
- https://github.com/fedora-python/lxml_html_clean/commit/9c5612ca33b941eec4178abf... Third Party Advisory
- https://github.com/fedora-python/lxml_html_clean/security/advisories/GHSA-xvp8-3... Third Party Advisory
Published: 6 Mar 2026 · Updated: 13 Mar 2026 · First seen: 9 Mar 2026