Vulnerability 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.
Related Weaknesses (CWE)
References
FAQ
What is CVE-2026-12539?
CVE-2026-12539 is a documented vulnerability. 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...
How severe is CVE-2026-12539?
CVSS scoring is not yet available for CVE-2026-12539. Check NVD for updates.
Is there a patch for CVE-2026-12539?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.