Affected: Datasolution AcyMailing extension for Joomla and WordPress

Joomla / WordPress Extension - acymailing.com - Missing authorization on subscription changes in AcyMailing 1.0.0 - 11.1.1 - An unauthenticated attacker who knows a subscriber's email address can unsubscribe that subscriber from one mailing list or from every mailing lists, without proving that the address is theirs. The affected feature also lets an attacker determine whether a given email address belongs to a subscriber of the site.