Docker Sandboxes enforce an HTTP/HTTPS egress allowlist but leave DNS resolution unfiltered. The embedded DNS server forwards any query to the host resolver when the network is internet‑connected, ignoring policy. Inside an untrusted workload, malicious data can be embedded in DNS labels and sent to an attacker‑controlled domain, providing a covert exfiltration channel.

Docker Sandboxes. No specific version information is supplied, so the impact applies to all releases that include the unfiltered DNS behavior.

The CVSS score of 5.7 indicates moderate risk. EPSS is not available and the vulnerability is not listed in CISA KEV. The attack vector is likely an internal, untrusted sandbox workload that can reach external DNS; the attacker requires control of a domain to receive the exfiltrated data. Because DNS traffic easily bypasses HTTP/HTTPS policies, the vulnerability permits data exfiltration even when network egress is otherwise restricted.