Medium severity · published Mar 5, 2026
CVE-2026-28350
lxml_html_clean: <base> tag injection through default Cleaner configuration
6.1
CVSS
0.3%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
Low
Integrity
Low
Availability
None
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 19% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
LX
lxml_html_clean · fedora-python
< 0.4.4 · source: vendor
LH
Lxml Html Clean · Fedoralovespython
before 0.4.4 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-28350
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-28350
Patch
https://github.com/fedora-python/lxml_html_clean/commit/9c5612ca33b941eec4178abf8a5294b103403f34
Exploit
https://github.com/fedora-python/lxml_html_clean/security/advisories/GHSA-xvp8-3mhv-424c
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