CVE-2026-12539 | Docker Sandboxes (sbx) blocks ICMP egress with an authorizer… | CVSS 5.7 MEDIUM

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.

Metadata

CVE ID: CVE-2026-12539
State: PUBLISHED
Assigner: Docker
Reserved: 2026-06-17 15:31 UTC
Published: 2026-06-18 13:51 UTC
Last updated: 2026-06-18 14:56 UTC
Primary CWE: CWE-923
CWE-923: Improper Restriction of Communication Channel to In…
Vendor / Product: Docker / Docker Sandboxes
Sources: cve.org · NVD

Severity & Metrics

5.7 MEDIUM CVSS 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

SSVC — CISA Coordinator

Exploitation: none
Automatable: no
Tech. Impact: partial

Affected products (1)

Vendor	Product	Platform	Versions
Docker	Docker Sandboxes	MacOS,Linux,Windows	0.14.0 < 0.33.0

Weakness (CWE)

CWE	Source	Description
CWE-665	cna	CWE-665: Improper Initialization
CWE-923	cna	CWE-923: Improper Restriction of Communication Channel to Intended Endpoints

CVSS scores (1)

Score	Severity	Version	Source	Vector
5.7	MEDIUM	4.0	cna	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

References (2)