MITLCache’s distributed mode exposes an unauthenticated ZeroMQ ROUTER socket on the default port. The server decodes incoming messages before running the request handler, passing any packet that contains Extension Code 1 to DeviceIPCWrapper.Deserialize. That function calls pickle.loads, which can execute arbitrary Python code. Consequently, a malicious ZMQ DEALER can cause the LMCache process to run attacker‑supplied code. If the process runs as root, the attacker gains full system privileges. The vulnerability is therefore a high‑severity Remote Code Execution flaw. The likely attack vector involves an attacker sending crafted ZMQ messages to the open port; because the server performs no authentication, the injected pickle payload is executed unconditionally.

All deployments of LMCache are affected, as the advisory does not list any specific version restrictions. This includes containerized installations that run the LMCache process as root and any configuration that enables the distributed mode over a routable interface.

With a CVSS score of 9.8 the flaw is critical. The EPSS score is not available, but the lack of authentication, combined with the default local binding on port 5555, provides an uncomplicated local exploitation path. If an operator exposes the port to external networks, remote attackers can also leverage the vulnerability. The flaw is not listed in CISA's KEV catalog, indicating no widely known public exploits, yet the conditions make it highly exploitable in practice.