In Mozilla Bleach before 3.3.0, a mutation XSS affects users calling bleach.clean with math or svg; p or br; and style, title, noscript, script, textarea, noframes, iframe, or xmp tags with strip_comments=False.
"https://github.com/pypa/advisory-database/blob/main/vulns/bleach/PYSEC-2021-865.yaml"