CVE-2026-12539

Docker Sandboxes ICMP egress restriction bypass after daemon restart

Published Jun 18, 2026 CVSS 4.0 · 5.1 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
CPEs cpe:2.3:a:docker:sandboxes:*:*:*:*:*:*:*:* cpe:2.3:a:docker:docker_sandboxes:*:*:*:*:*:*:*:*
Vendors & Products Docker sandboxes
Type Values Removed Values Added
First Time appeared Docker sandboxes
CPEs cpe:2.3:a:docker:sandboxes:*:*:*:*:*:*:*:*
Vendors & Products Docker sandboxes
Metrics cvssV4_0

{'score': 5.7, 'vector': 'CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N'}

cvssV4_0

{'score': 5.1, 'vector': 'CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N'}

Type Values Removed Values Added
First Time appeared Docker
Docker docker Sandboxes
Vendors & Products Docker
Docker docker Sandboxes
Type Values Removed Values Added
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.
Title Docker Sandboxes ICMP egress restriction bypass after daemon restart
Weaknesses CWE-665
CWE-923
References
Metrics cvssV4_0

{'score': 5.7, 'vector': 'CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
Docker
Published
Updated
Aug 13, 2026, 1:33 PM
Reserved
Jun 17, 2026, 3:31 PM
Status
Awaiting Analysis
Published
Jun 18, 2026, 2:17 PM
Modified
Oct 26, 2026, 11:10 AM