Docmost: Privilege Escalation - ADMIN Can Invite Users as OWNER

Docmost is open-source collaborative wiki and documentation software. Prior to 0.90.1, an authenticated workspace ADMIN can use the workspace invitation flow to invite an external email address with the OWNER role because the role ceiling does not prevent ADMIN users from granting privileges above their own. When the invitation is accepted, the new account receives OWNER-level permissions, allowing the ADMIN to create a backdoor OWNER account or promote a colluding external user to the workspace's highest privilege level. This issue is fixed in version 0.90.1.