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Description

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.

PUBLISHED Reserved 2026-06-17 | Published 2026-06-18 | Updated 2026-06-18 | Assigner Docker




MEDIUM: 5.7CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

Problem types

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

CWE-665: Improper Initialization

Product status

Default status
unaffected

0.14.0 (semver) before 0.33.0
affected

References

docs.docker.com/ai/sandboxes/ product

github.com/docker/sbx-releases/releases/tag/v0.33.0 release-notes

cve.org (CVE-2026-12539)

nvd.nist.gov (CVE-2026-12539)

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