Amazon Linux 2023: CVE-2021-43818: Important priority package update for python-lxml

Description

lxml is a library for processing XML and HTML in the Python language. Prior to version 4.6.5, the HTML Cleaner in lxml.html lets certain crafted script content pass through, as well as script content in SVG files embedded using data URIs. Users that employ the HTML cleaner in a security relevant context should upgrade to lxml 4.6.5 to receive a patch. There are no known workarounds available. There's a flaw in python-lxml's HTML Cleaner component, which is responsible for sanitizing HTML and Javascript. An attacker who is able to submit a crafted payload to a web service using python-lxml's HTML Cleaner may be able to trigger script execution in clients such as web browsers. This can occur because the HTML Cleaner did not remove scripts within SVG images in data URLs such as <img src="">. XSS can result in impacts to the integrity and availability of the web page, as well as a potential impact to data confidentiality in some circumstances.