--------------------------------
**Security fixes**
* ``bleach.clean`` behavior parsing embedded MathML and SVG content
with RCDATA tags did not match browser behavior and could result in
a mutation XSS.
Calls to ``bleach.clean`` with ``strip=False`` and ``math`` or
``svg`` tags and one or more of the RCDATA tags ``script``,
``noscript``, ``style``, ``noframes``, ``iframe``, ``noembed``, or
``xmp`` in the allowed tags whitelist were vulnerable to a mutation
XSS.
This security issue was confirmed in Bleach version v3.1.1. Earlier
versions are likely affected too.
Anyone using Bleach <=v3.1.1 is encouraged to upgrade.
https://bugzilla.mozilla.org/show_bug.cgi?id=1621692
**Backwards incompatible changes**
None
**Features**
None
**Bug fixes**
None