Use-after-free vulnerability in OpenSMTPD before 5.7.2 allows remote attackers to cause a denial of service (crash) or execute arbitrary code via vectors involving req_ca_vrfy_smtp and req_ca_vrfy_mta.
lists.fedoraproject.org/pipermail/package-announce/2015-November/170448.html
lists.fedoraproject.org/pipermail/package-announce/2015-October/169600.html
www.openwall.com/lists/oss-security/2015/10/03/1
www.securityfocus.com/bid/76975
bugzilla.redhat.com/show_bug.cgi?id=1268793
www.opensmtpd.org/announces/release-5.7.2.txt
www.qualys.com/2015/10/02/opensmtpd-audit-report.txt