CVE-2026-12039 (GCVE-0-2026-12039)
Vulnerability from cvelistv5 – Published: 2026-06-18 13:48 – Updated: 2026-08-13 13:33
VLAI
EPSS
VEX
Title
Docker Sandboxes network egress allowlist bypass via unfiltered DNS resolution
Summary
Docker Sandboxes (sbx) enforces an HTTP/S-only egress allowlist but does not apply it to DNS resolution: the per-network embedded DNS server forwards any queried name to the host resolver whenever the network is internet-connected, without consulting the policy. A workload inside a sandbox, which the threat model treats as untrusted, can therefore encode data into DNS labels for an attacker-controlled domain and exfiltrate it through a DNS covert channel, bypassing the configured allowlist.
Severity
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-06-18 15:00 UTC
CWE
- CWE-923 - Improper Restriction of Communication Channel to Intended Endpoints
Assigner
References
2 references
| URL | Tags |
|---|---|
| https://docs.docker.com/ai/sandboxes/ | product |
| https://github.com/docker/sbx-releases/releases/t… | release-notes |
Impacted products
1 product
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Docker | Docker Sandboxes |
Affected:
0.13.0 , < 0.33.0
(semver)
cpe:2.3:a:docker:docker_sandboxes:*:*:*:*:*:*:*:* |
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Sightings
| Author | Source | Type | Date | Other |
|---|
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Vulnerability timeline
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
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They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.