vulntracker.iovulntracker.io
© 2026 vulntracker.io

CVE-2026-12039

Docker Sandboxes network egress allowlist bypass via unfiltered DNS resolution

MEDIUM
5.7
CVSS Score
Published: June 18, 2026 at 01:48 PM UTC
Updated: October 26, 2026 at 11:10 AM UTC
2 products affected across 1 vendorDocker SandboxesDocker Sandboxes

Using Docker Sandboxes by Docker?

Get instant alerts when new vulnerabilities affect Docker Sandboxes - before attackers find them.

Real-time alertsTrack your software stackFree plan available
Start FreeSign In
Severity
MEDIUM5.7
Exploit prediction
EPSS 0.1%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Docker Sandboxes· Docker
95%
All versions
Docker Sandboxes· Docker
90%
0.13.0 ≤ v < 0.33.00.13.0
Affected range stops below 0.33.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

References (2)

Product
Source: cverecord
https://docs.docker.com/ai/sandboxes/
Release Notes
Source: cverecord
https://github.com/docker/sbx-releases/releases/tag/v0.33.0

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.7MEDIUMDocker
Vector?

Quick Info

StatusAWAITING ANALYSIS
CWE
CWE-923

Get alerted

Stop reading CVE feeds looking for your own stack

Track the products you run and VulnTracker tells you when a new CVE affects them — with what is known about fixing it, and nothing about the rest.

Create accountSign in
Free plan, no card