The Popup Builder by OptinMonster WordPress plugin before 2.12.2 does not ensure that the campaign to be loaded via some shortcodes is actually a campaign, allowing any authenticated users such as subscriber to retrieve the content of arbitrary posts, like draft, private or even password protected ones.

The Popup Builder by OptinMonster WordPress plugin before 2.12.2 does not ensure that the campaign to be loaded via some shortcodes is actually a campaign, allowing any authenticated users such as subscriber to retrieve the content of arbitrary posts, like draft, private or even password protected ones.