LibEtPan through 1.9.4, as used in MailCore 2 through 0.6.3 and other products, has a STARTTLS buffering issue that affects IMAP, SMTP, and POP3. When a server sends a "begin TLS" response, the client reads additional data (e.g., from a meddler-in-the-middle attacker) and evaluates it in a TLS context, aka "response injection."
In libetpan a null pointer dereference in mailimap_mailbox_data_status_free in low-level/imap/mailimap_types.c was found that could lead to a remote denial of service or other potential consequences.