CVE-2026-12539

Severity CVSS v4.0:

MEDIUM

Type:

Unavailable / Other

Publication date:

18/06/2026

Last modified:

30/06/2026

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.

Impact

Vector 4.0

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 CVSS v4.0 Severity and Metrics:

Base Score: 5.70 MEDIUM
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

Attack Vector (AV): Local
Attack Complexity (AC): Low
Attack Requirements (AT): Present
Privileges Required (PR): Low
User Interaction (UI): None
Confidentiality (VC): High
Integrity (VI): None
Availability (VA): None
Confidentiality (SC): None
Integrity (SI): None
Availability (SA): None

Base Score 4.0

5.70

Severity 4.0

MEDIUM

CVE-2026-12539

Description

Impact

References to Advisories, Solutions, and Tools