Nextcloud: BOLA/IDOR in Out-of-Office API allows any authenticated user to read other users' absence data

Summary The Out-of-Office OOO API endpoints at /ocs/v2.php/apps/dav/api/v1/outOfOffice/userId and /ocs/v2.php/apps/dav/api/v1/outOfOffice/userId/now suffer from a Broken Object Level Authorization BOLA vulnerability. Any authenticated user can retrieve the out-of-office data of any other user by...