mutt -- denial of service

Tavis Ormandy reports:

    rfc822.c in Mutt through 2.0.4 allows remote attackers to cause a
    denial of service (mailbox unavailability) by sending email messages
    with sequences of semicolon characters in RFC822 address fields
    (aka terminators of empty groups). A small email message from the
    attacker can cause large memory consumption, and the victim
    may then be unable to see email messages from other persons.