[MFSA-2022-38] Security Vulnerabilities fixed in Thunderbird 102.2.1

CVE-2022-3032: Remote content specified in an HTML document that was nested inside an iframe's srcdoc attribute was not blocked (moderate)
When receiving an HTML email that contained an <code>iframe</code> element, which used a <code>srcdoc</code> attribute to define the inner HTML document, remote objects specified in the nested document, for example images or videos, were not blocked. Rather, the network was accessed, the objects were loaded and displayed.

CVE-2022-3033: Leaking of sensitive information when composing a response to an HTML email with a META refresh tag (high)
If a Thunderbird user replied to a crafted HTML email containing a <code>meta</code> tag, with the <code>meta</code> tag
having the <code>http-equiv="refresh"</code> attribute, and the content attribute specifying an URL, then
Thunderbird started a network request to that URL, regardless of the configuration to block
remote content. In combination with certain other HTML elements and attributes in the email,
it was possible to execute JavaScript code included in the message in the context of the
message compose document.
The JavaScript code was able to perform actions including, but probably not limited
to, read and modify the contents of the message compose document, including the quoted
original message, which could potentially contain the decrypted plaintext of encrypted data
in the crafted email.
The contents could then be transmitted to the network, either to the URL specified in the META refresh tag,
or to a different URL, as the JavaScript code could modify the URL specified in the document.
This bug doesn't affect users who have changed the default Message Body display setting to
'simple html' or 'plain text'.

CVE-2022-3034: An iframe element in an HTML email could trigger a network request (moderate)
When receiving an HTML email that specified to load an <code>iframe</code> element from a remote location, a request to the remote document was sent. However, Thunderbird didn't display the document.

CVE-2022-36059: Matrix SDK bundled with Thunderbird vulnerable to denial-of-service attack (moderate)
Thunderbird users who use the Matrix chat protocol were vulnerable to a denial-of-service attack. An adversary sharing a room with a user had the ability to carry out an attack against affected clients, making it not show all of a user's rooms or spaces and/or causing minor temporary corruption.