Researchers have discovered vulnerabilities in PGP and S/MIME technologies used to encrypt email.
The problem resides in how email clients use these plug-ins to decrypt HTML-based emails.
Individuals and companies are encouraged to disable PGP and/or S/MIME in their email clients for now.
Instead, use a third-party client like Signal to encrypt iOS and Android emails.
But if you don’t use PGP or S/MIME for email encryption, then don't worry!