The c-client library in Internet Message Access Protocol (IMAP) dated before 2002 RC2, as used by Pine 4.20 through 4.44, allows remote attackers to cause a denial of service (client crash) via a MIME-encoded email with Content-Type header containing an empty boundary field.
https://euvd.enisa.europa.eu/vulnerability/EUVD-2002-2303
http://www.securityfocus.com/bid/5301