CVE-2026-12039
MEDIUM
MEDIUM
Priority: 0.01
BB Relevance:
36/100
Published: 2026-06-18
Modified: 2026-10-26
First seen: 2026-10-29
Status: active
Attack Surface
Low Complexity
No Interaction
Conf. Impact
CVSS Vector Breakdown
AV:
Local
AC:
Low
PR:
Low
UI:
None
S:
X
AT:
Present
VC:
High
VI:
None
VA:
None
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.