An issue was discovered in powermail extension through 12.3.5 for TYPO3. It fails to validate the mail parameter of the confirmationAction, resulting in Insecure Direct Object Reference (IDOR). An unauthenticated attacker can use this to display the user-submitted data of all forms persisted by the extension. This can only be exploited when the extension is configured to save submitted form data to the database (plugin.tx_powermail.settings.db.enable=1), which however is the default setting of the extension. The fixed versions are 7.5.0, 8.5.0, 10.9.0, and 12.4.0