Startup TLS Trust Issue Enables Credential Disclosure

OfflineIMAP before 8.0.3 trusts the server with their STARTTLS capability prior to authentication, which allows STRIPTLS/man-in-the-middle attacks, taking over the connection and extracting account credentials in cleartext.

offlineimap before 6.3.4 added support for SSL server certificate validation but it is still possible to use SSL v2 protocol, which is a flawed protocol with multiple security deficiencies.

offlineimap before 6.3.2 does not check for SSL server certificate validation when "ssl = yes" option is specified which can allow man-in-the-middle attacks.