[Users] Libetpan vulnerability - Claws users beware

[Brian Morrison]

I have just noticed that libetpan is subject to a vulnerability
detailed as CVE-2020-15953 so Claws users should be alert to updates
for their distro or should seek out fixed versions.

Details can be found here:

https://github.com/dinhvh/libetpan/issues/386

It appears that any such response will abort your IMAP, SMTP or POP
session as there is no intended to be anything sent after a STARTTLS
response.

-- 

Brian