A mutation XSS affects users calling bleach.clean with noscript and a raw tag (see below) in the allowed/whitelisted tags option.
v3.1.1
modify bleach.clean calls to not whitelist noscript and one or more of the following raw tags:
title
textarea
script
style
noembed
noframes
iframe
xmp
A strong Content-Security-Policy without unsafe-inline and unsafe-eval <code>script-src</code>s) will also help mitigate the risk.
If you have any questions or comments about this advisory:
{
"github_reviewed_at": "2020-02-19T19:43:47Z",
"github_reviewed": true,
"severity": "MODERATE",
"nvd_published_at": "2020-03-24T22:15:00Z",
"cwe_ids": [
"CWE-79"
]
}