An issue was discovered in the powermail extension through 12.4.0 for TYPO3. It fails to validate the mail parameter of the createAction, resulting in Insecure Direct Object Reference (IDOR) in some configurations. An unauthenticated attacker can use this to display user-submitted data of all forms persisted by the extension. The fixed versions are 7.5.1, 8.5.1, 10.9.1, and 12.4.1.

powermail TYPO3 extension has Insecure Direct Object Reference