CVEvulnerability

CVE-2026-12039

5.7 MEDIUM Published 2026-06-18 Modified 2026-10-26 Official page ↗
Status
Awaiting Analysis
Published
2026-06-18
Last modified
2026-10-26
Assigner
[email protected]
CVSS 4.0 ([email protected])
5.7 MEDIUM — 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
Weaknesses
CWE-923

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.

Related

Weakness · CWE (1)

  • CWE-923 Improper Restriction of Communication Channel to Intended Endpoints weakness

References