CVE-2026-18171 Docker Sandboxes read-only runtime mount writable through its shared-export alias

Docker Sandboxes sbx applies the read-only intent of a runtime host mount to the in-guest container bind only: the underlying virtio-fs host-edge grant is added to the sandbox's policy-share allowlist with no access mode. The directory stays writable at its shared-export path, so unprivileged cod...