CVE-2026-12539: Docker Sandboxes

Medium severity, CVSS 5.7. EPSS: 0.1% chance of exploitation in the next 30 days.

Docker Sandboxes (sbx) blocks ICMP egress with an authorizer applied only at network-creation time, and does not re-apply it to networks rebuilt from disk when the Docker daemon restarts, so a restart-surviving sandbox forwards ICMP to arbitrary hosts. A workload inside a sandbox, which the threat model treats as untrusted, can therefore defeat the documented ICMP egress block to perform network reconnaissance and exfiltrate data over an ICMP covert channel, regardless of the configured allowlist.

Affected products

• Docker Docker Sandboxes: from 0.14.0, before 0.33.0 (fixed in 0.33.0)

Published 2026-06-18. Last modified 2026-08-13.