Bugzilla 2.16rc1 through 2.22.7, 3.0.x through 3.3.x, 3.4.x before 3.4.12, 3.5.x, 3.6.x before 3.6.6, 3.7.x, 4.0.x before 4.0.2, and 4.1.x before 4.1.3 does not prevent changes to the confirmation e-mail address (aka old_email field) for e-mail change notifications, which makes it easier for remote attackers to perform arbitrary address changes by leveraging an unattended workstation.