XSS in Fedoralovespython Lxml HTML Clean

CVE-2024-52595

lxml_html_clean is a project for HTML cleaning functionalities copied from `lxml.html.clean`. Prior to version 0.4.0, the HTML Parser in lxml does not properly handle context-switching for special HTML tags such as `<svg>`, `<math>` and `<noscript>`. This behavior deviates from how web browsers parse and interpret such tags. Specifically, content in CSS comments is ignored by lxml_html_clean but may be interpreted differently by web browsers, enabling malicious scripts to bypass the cleaning process. This vulnerability could lead to Cross-Site Scripting (XSS) attacks, compromising the security of users relying on lxml_html_clean in default configuration for sanitizing untrusted HTML content. Users employing the HTML cleaner in a security-sensitive context should upgrade to lxml 0.4.0, which addresses this issue. As a temporary mitigation, users can configure lxml_html_clean with the following settings to prevent the exploitation of this vulnerability. Via `remove_tags`, one may specify tags to remove - their content is moved to their parents' tags. Via `kill_tags`, one may specify tags to be removed completely. Via `allow_tags`, one may restrict the set of permissible tags, excluding context-switching tags like `<svg>`, `<math>` and `<noscript>`.

Vulnerability class: XSS (Cross-Site Scripting)

EPSS: 0.005 (39.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.7 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:H.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2024-52595?
CVE-2024-52595 is a high-severity vulnerability in Fedoralovespython Lxml HTML Clean, classified under Cross-site Scripting. CVSS score: 7.7/10. Published 2024-11-19.
How severe is CVE-2024-52595?
High severity. CVSS v3 base score is 7.7 out of 10.