Docker Layer 2 ICC Bug refers to a security vulnerability in Docker's inter-container communication (ICC) implementation. When Docker containers are created, they are automatically connected to a bridge network that enables communication between containers. The vulnerability occurs when administrators attempt to disable ICC for security purposes. Despite disabling ICC through Docker's configuration, the underlying network implementation still allows raw ethernet frames to pass between containers at Layer 2 of the network stack. This bypass mechanism enables containers to establish unexpected data transfer channels using raw sockets, effectively circumventing the intended security restriction. The bug demonstrates that Docker's ICC disable feature does not provide complete network isolation between containers as expected. Security implications include potential data exfiltration, lateral movement between containers, and unauthorized communication channels that may not be detected by standard network monitoring tools focused on higher-layer protocols.