Improper Neutralization of Input During Web Page Generation in LXML
Date: 2022-05
Affected: pip/lxml
Attack vector: xss
Category: vulnerability-disclosure
Severity: Medium
CVE: CVE-2018-19787
CWE: CWE-79
CVSS: 6.1 (CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N)

An issue was discovered in lxml before 4.2.5. lxml/html/clean.py in the lxml.html.clean module does not remove javascript: URLs that use escaping, allowing a remote attacker to conduct XSS attacks, as demonstrated by "j a v a s c r i p t:" in Internet Explorer. This is a similar issue to CVE-2014-3146.


Mitigations:

Architectural layers (MAESTRO):