Summary
CVE-2026-6406: Docker Desktop --use-api-socket bypasses Enhanced Container Isolation by using Mounts instead of Binds.
Affected Asset
Docker Desktop 4.41.0 (Docker CLI --use-api-socket bypass on Enhanced Container Isolation).
Affected Endpoint
Docker CLI / Docker Engine API socket mount
Prerequisites
Docker Desktop 4.41.0 with Enhanced Container Isolation (ECI) enabled; attacker with access to the Docker CLI able to pass --use-api-socket.
Steps to Reproduce
Use the Docker CLI with ECI enabled and pass --use-api-socket; mount a socket into a container that accesses containerd/Docker socket mounts to reach host processes.
Evidence
Public advisory (Noxen) and NVD entry; confirmed container escape demonstrations on Proxmox / LXC homelab setups.
Impact
Privilege escalation to host via bypass of Enhanced Container Isolation; an attacker who can control container runtime can run privileged processes or leak host credentials.
Root Cause
runc did not properly restrict access to host-side file descriptors within the container's /proc view, allowing a malicious container to reference and chdir into leaked descriptors.
Remediation
Update runc to 1.1.12+; on Proxmox: apt update && apt dist-upgrade (pve-container / lxc-pve packages from Feb 2024); verify with runc --version.
Verification Steps
Confirm Docker Desktop version (docker version) is not 4.41.0 with --use-api-socket active; verify ECI settings do not allow the socket mount via HostConfig.Mounts.