stunnel 4.40 and 4.41 might allow remote attackers to execute arbitrary code or cause a denial of service (heap memory corruption) via unspecified vectors.
https://exchange.xforce.ibmcloud.com/vulnerabilities/69318
https://bugzilla.redhat.com/show_bug.cgi?id=732068
http://www.stunnel.org/pipermail/stunnel-announce/2011-August/000059.html
http://www.securityfocus.com/bid/49254
http://www.openwall.com/lists/oss-security/2011/08/19/6
http://www.openwall.com/lists/oss-security/2011/08/19/18
http://stunnel.org/?page=sdf_ChangeLog