Docker Sandboxes vulnerabilities

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 code inside the sandbox can derive that path and write to a host directory the operator attached read-only.

The vulnerability in Docker Sandboxes (sbx) is that the ICMP egress block is applied only at network creation time and is not re-applied to networks rebuilt from disk after a Docker daemon restart. Consequently, a sandbox that survives a restart can forward ICMP to arbitrary hosts.

A vulnerability in Docker Sandboxes (sbx) allows bypassing the HTTP/S-only egress allowlist via DNS tunneling. The embedded DNS server forwards queries to the host resolver without policy enforcement, enabling untrusted workloads to exfiltrate data encoded in DNS labels.