The Simplenews module 6.x-1.x before 6.x-1.4, 6.x-2.x before 6.x-2.0-alpha4, and 7.x-1.x before 7.x-1.0-rc1 for Drupal reveals the email addresses of new mailing list subscribers when confirmation is required, which allows remote attackers to obtain sensitive information via the confirmation page.