Authenticated server-memory disclosure via projection misplanning

Memory disclosure in PostgreSQL 11 through 13 allows remote authenticated users to read arbitrary server-memory bytes via a crafted query. Stacked ProjectionPath nodes cause the planner to reuse a child path with the wrong target list, producing an incorrect parallel-sort plan that returns bytes from unrelated memory. Any database login suffices under the default worker configuration; max_worker_processes set to zero blocks known query variants, and no object-creation privilege is required.