The strchr function in procmime.c in Claws Mail (aka claws-mail) 3.8.1 allows remote attackers to cause a denial of service (NULL pointer dereference and crash) via a crafted email.
https://bugzilla.redhat.com/show_bug.cgi?id=862578
http://www.thewildbeast.co.uk/claws-mail/bugzilla/show_bug.cgi?id=2743
http://www.securityfocus.com/bid/55837
http://www.openwall.com/lists/oss-security/2012/10/10/3
http://www.openwall.com/lists/oss-security/2012/10/09/3
http://www.openwall.com/lists/oss-security/2012/10/09/1
http://lists.opensuse.org/opensuse-updates/2012-10/msg00064.html