Debian Linux Security Advisory 2242-1 – It was discovered that the STARTTLS implementation of the Cyrus IMAP server does not properly restrict I/O buffering, which allows man-in-the-middle attackers to insert commands into encrypted IMAP, LMTP, NNTP and POP3 sessions by sending a cleartext command that is processed after TLS is in place.
Source: Debian Security Advisory 2242-1
