Matt Wright FormMail 1.9 and earlier allows remote attackers to send spam or anonymous e-mail by injecting a newline character followed by CC:, BCC:, or additional TO: fields in the email and realname CGI variables.
https://exchange.xforce.ibmcloud.com/vulnerabilities/8013
http://www.securityfocus.com/bid/3955
http://www.scriptarchive.com/readme/formmail.html#history
http://archives.neohapsis.com/archives/bugtraq/2002-01/0307.html