PHP remote file inclusion vulnerability in kmitaadmin/kmitam/htmlcode.php in Kmita Mail 3.0 and earlier, when registerglobals is enabled, allows remote attackers to execute arbitrary PHP code via a URL in the file parameter.
The S/MIME specification allows a Cipher Block Chaining (CBC) malleability-gadget attack that can indirectly lead to plaintext exfiltration, aka EFAIL.
In KDE KMail 19.12.3 (aka 5.13.3), the SMTP STARTTLS option is not honored (and cleartext messages are sent) unless "Server requires authentication" is checked.