Lmcache: Duplicate Advisory: Remote code execution via unsafe deserialization in multiprocess mode transport

LMCache multiprocess mode opens an unauthenticated ZeroMQ ROUTER socket for worker processes to share cache blocks. Messages are msgpack-encoded, and extension code 1 is passed to DeviceIPCWrapper.Deserialize, which uses pickle.loads to deserialize data. This unsafe deserialization occurs before request handling, allowing a single unauthenticated ZMQ DEALER message to execute arbitrary code as the LMCache process user. By default, the transport binds to localhost, but if the operator sets a routable address via the --host option, remote exploitation is possible. Official container images run the process as root, increasing the severity of this remote code execution vulnerability.

Successful exploitation allows unauthenticated remote attackers to execute arbitrary code with the privileges of the LMCache process, which is root in official container images. This can lead to full system compromise, data loss, or service disruption. The vulnerability affects deployments where the transport is exposed to routable networks.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, operators should ensure the transport socket is bound only to localhost and not exposed to untrusted networks. Avoid setting the --host option to a routable address unless necessary and secure the environment accordingly.