The from_format function in ssmtp.c in ssmtp 2.61 and 2.62, in certain configurations, uses uninitialized memory for the From: field of an e-mail message, which might allow remote attackers to obtain sensitive information (memory contents) in opportunistic circumstances by reading a message.
https://exchange.xforce.ibmcloud.com/vulnerabilities/45038
https://bugs.gentoo.org/234391
http://www.vupen.com/english/advisories/2008/2597
http://www.securityfocus.com/bid/31094
http://www.openwall.com/lists/oss-security/2008/09/11/2