In OpenStack Manila before 23.0.1, multiple Manila API operations on public shares do not verify that the caller owns the share. The API controllers authorize operations against the caller's own project context, then load a foreign public share without re-authorizing against the share's actual owner. This affects the following operations: allow_access: grant data-plane read/write access to another tenant's share; deny_access: revoke the owner's existing access rules; update_access: escalate access level (e.g., ro to rw); create_share_backup: exfiltrate share data via a backup created under the attacker's project; soft_delete: move a foreign share to the recycle bin; restore: interfere with the owner's deletion workflow; export location metadata: create, update, and delete metadata on foreign export locations; access rule listing: disclose IPs, usernames, and CephFS keys. Any authenticated project member can exploit these operations on any public share. The share UUID is visible since the share is public.