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.

Format string vulnerabilities in the (1) die or (2) log_event functions for ssmtp before 2.50.6 allow remote mail relays to cause a denial of service and possibly execute arbitrary code.

The log_event function in ssmtp 2.50.6 and earlier allows local users to overwrite arbitrary files via a symlink attack on the ssmtp.log temporary log file.