admin/index.php in Gregory Kokanosky phpMyNewsletter 0.8 beta5 and earlier provides access to configuration modification before login, which allows remote attackers to cause a denial of service (loss of configuration data), and possibly perform direct static code injection, via a saveGlobalconfig action.

admin/send_mod.php in Gregory Kokanosky phpMyNewsletter 0.8 beta5 and earlier prints a Location header but does not exit when administrative credentials are missing, which allows remote attackers to compose an e-mail message via a post with the subject, message, format, and list_id fields; and send the message via a direct request for the MsgId value under admin/.

SQL injection vulnerability in archives.php in Gregory Kokanosky (aka Greg's Place) phpMyNewsletter 0.8 beta 5 and earlier allows remote attackers to execute arbitrary SQL commands via the msg_id parameter.

PHP remote file inclusion vulnerability in customize.php for phpMyNewsletter 0.6.10 allows remote attackers to execute arbitrary PHP code via the l parameter.