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.
The issue has been resolved in lxml 4.6.5.
None.
The issues are tracked under the report IDs GHSL-2021-1037 and GHSL-2021-1038.