Multiple access control defects exist in the sharing link module. A valid ticket issued for one share can be reused against another because tickets are not bound to the target share UUID, affecting the `ShareTicketManage.validateTicket()` function at the 'POST /de2api/share/proxyInfo' endpoint. The 'POST /de2api/share/validate' endpoint allows the issuance of a LinkToken after password verification without requiring a ticket, bypassing the mandatory ticket policy. Furthermore, the 'POST /de2api/ticket/saveTicket' and 'POST /de2api/ticket/delTicket' endpoints lack share-ownership checks, enabling authenticated users to modify, rebind, or delete tickets belonging to others, which can lead to a denial of service. Additionally, the 'GET /de2api/share/queryRelationByUserId/{uid}' endpoint allows authenticated users to enumerate share mappings of other users via the `uid` variable.