CVE-2026-12039: Docker Sandboxes network egress allowlist bypass via unfiltered DNS resolution
Docker · Docker Sandboxes
Vendor fix available · Affected: Docker Sandboxes · Exploitation: unlikely (under 1%)
Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.
Higher than 1% of scored CVEs
DescriptionCVE.org
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.
Affected products1
From the CVE record. A product or version that is not listed is unknown, not unaffected.
- Docker · Docker Sandboxesfrom 0.13.0 before 0.33.0
On the Atlas
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CoverageNo articles yet
No CyberSIXT article names CVE-2026-12039 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.