What’s Vulnerable › Vulnerabilities

CVE-2026-12539: Docker Sandboxes ICMP egress restriction bypass after daemon restart

• Severity: medium (CVSS 5.7 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-06-18 · updated 2026-10-26
• Weakness: CWE-665

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.

Affected products

• Docker Sandboxes: from 0.14.0 before 0.33.0 — fixed in 0.33.0

How to fix

Upgrade to a fixed version: Docker Sandboxes 0.33.0. Check the vendor advisory for mitigations.

References

• https://docs.docker.com/ai/sandboxes/
• https://github.com/docker/sbx-releases/releases/tag/v0.33.0

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