capgo.app: Capgo backend before 12.127.5 Privilege Escalation via role_bindings PATCH

Capgo (capgo.app backend) before 12.127.5 contains an authorization flaw in the PATCH /private/role_bindings/:binding_id endpoint. The handler verifies that the newly assigned role's priority rank does not exceed the caller's own rank, but — unlike the DELETE handler — it never checks the rank of the role currently bound to the target binding. An authenticated user holding the org_admin role (rank 90) can therefore change an org_super_admin binding (rank 95) to a lower-privileged role such as org_member (rank 75). Because the prevent_last_super_admin_binding_delete database trigger fires only BEFORE DELETE and not on UPDATE, an org_admin can demote every org_super_admin, leaving the organization with no super administrator. The issue is fixed in 12.127.5.