{"id":"CVE-2026-12039","summary":"Docker Sandboxes network egress allowlist bypass via unfiltered DNS resolution","details":"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.","modified":"2026-07-08T07:37:03.809242959Z","published":"2026-06-18T13:48:14.682Z","database_specific":{"cwe_ids":["CWE-923"],"cna_assigner":"Docker","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/12xxx/CVE-2026-12039.json"},"references":[{"type":"WEB","url":"https://docs.docker.com/ai/sandboxes/"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/12xxx/CVE-2026-12039.json"},{"type":"ADVISORY","url":"https://github.com/docker/sbx-releases/releases/tag/v0.33.0"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-12039"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/docker/sbx-releases","events":[{"introduced":"0"},{"fixed":"e4809b108ff941fbd3dc8ab1edd8755af78ddc07"}],"database_specific":{"source":["AFFECTED_FIELD","REFERENCES"],"extracted_events":[{"introduced":"0.13.0"},{"fixed":"0.33.0"}]}}],"versions":["v0.31.0-rc1","v0.30.0-rc2","v0.30.0-rc1","v0.30.0","v0.29.0-rc1","v0.29.0","v0.28.3","v0.28.2","v0.28.1-rc2","v0.28.1","v0.28.0","v0.27.0","v0.26.1","v0.25.0","dev-ebc3fbe","dev-e54ee33","dev-dc73246","dev-c7702ef","dev-c13a59d","dev-bad9503","dev-ad0ca5e","dev-a5207e0","dev-921c1c7","dev-8fc2763","dev-793e764","dev-78ed158","dev-438ebd7","dev-2631810","dev-1f51dc0","dev-02f174c","v0.24.2","v0.24.1","v0.23.0","v0.21.0","v0.20.0","v0.19.0","v0.18.7","v0.18.6","v0.18.5","v0.18.4","v0.18.3","v0.18.2","v0.17.0","v0.16.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-12039.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V4","score":"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"}]}