Buffer overflow in copy.c in Mutt before 1.5.23 allows remote attackers to cause a denial of service (crash) via a crafted RFC2047 header line, related to address expansion.
Mutt 1.5.13 and earlier does not properly use the --status-fd argument when invoking GnuPG, which prevents Mutt from visually distinguishing between signed and unsigned portions of OpenPGP messages with multiple components, which allows remote attackers to forge the contents of a message without detection.