wp-mail.php in WordPress before 4.7.1 might allow remote attackers to bypass intended posting restrictions via a spoofed mail server with the mail.example.com name.
https://wpvulndb.com/vulnerabilities/8719
https://wordpress.org/news/2017/01/wordpress-4-7-1-security-and-maintenance-release/
https://github.com/WordPress/WordPress/commit/061e8788814ac87706d8b95688df276fe3c8596a
https://codex.wordpress.org/Version_4.7.1
http://www.securitytracker.com/id/1037591
http://www.securityfocus.com/bid/95406