CVE-2026-12039

Summary

Docker Sandboxes (sbx) enforces an HTTP/S-only egress allowlist but does not apply it to DNS resolution: the per-network embedded DNS server forwards any queried name to the host resolver whenever the network is internet-connected, without consulting the policy. A workload inside a sandbox, which the threat model treats as untrusted, can therefore encode data into DNS labels for an attacker-controlled domain and exfiltrate it through a DNS covert channel, bypassing the configured allowlist.

Affected Software

VendorProductVersion RangeStatus
DockerDocker Sandboxes0.13.0 < 0.33.0affected

Weaknesses

  • CWE-923: CWE-923: Improper Restriction of Communication Channel to Intended Endpoints

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

References