Docker Sandboxes network egress allowlist bypass via unfiltered DNS resolution (Docker Docker Sandboxes)
At a glance
- Source
- NVD
- EPSS
- EPSS 0.10 % · percentile 1 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- Docker
- NVD status
- Awaiting Analysis
Description
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.
Weaknesses (CWE)
- CWE-923 — Improper Restriction of Communication Channel to Intended Endpoints
References
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 4.0 | MEDIUM 5.7 | 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 | Docker |
| CVSS 4.0 | MEDIUM 5.7 | 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X | NVD · security@docker.com (Secondary) |
European references
- ENISA EUVD · EUVD-2026-37892
- GCVE · GCVE-0-2026-12039
Affected products
| Product | Versions |
|---|---|
| Docker · Docker Sandboxes | affected 0.13.0 < 0.33.0 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |