CVE-2025-32444 (CVSS 10): Critical RCE Flaw in vLLM’s Mooncake Integration Exposes AI Infrastructure

This security issue gives an attacker the ability to execute arbitrary code remotely on vLLM instances due to insecure deserialization within the Mooncake integration. The following protection guardrails can further prevent the following steps an attacker can take: When an attacker sends a specially crafted serialized Python object to the vulnerable recv_pyobj() function, which then attempts to deserialize it using pickle.loads(), Python Deserialization Protection helps prevent the initial remote code execution by intercepting this deserialization process and restricting potentially harmful function calls embedded within the payload, such as those designed to initiate system commands or access sensitive files. If the attacker's code, perhaps through a partially successful deserialization, then attempts to execute operating system commands directly from within the Python environment, Python OS Command Injection Prevention would monitor and block these unauthorized system-level actions, for instance, preventing the execution of shell commands intended to download additional malware or exfiltrate data. To establish persistent control or interactive access after gaining an initial foothold, an attacker might try to set up a reverse shell; Reverse Shell Protection thwarts this by preventing the compromised process from binding shell input, output, and error streams to a network socket, thereby blocking the creation of such interactive command channels. In scenarios where the vulnerable vLLM service is running inside a container, and the attacker, having achieved code execution, attempts to introduce and run new malicious binaries or scripts that were not part of the original, trusted container image, Container Drift Protection (Binaries & Scripts) would block their execution, thus preserving the integrity of the containerized environment. Finally, should an attacker manage to place malicious tools or scripts in non-standard file system locations, such as temporary directories, and then attempt to execute them to further their attack, Process Path Exec Allow enforces execution policies based on pre-approved path allowlists, preventing these unauthorized programs from running from untrusted locations.

• T1203: Exploitation for Client Execution: The attacker exploits a vulnerability in the vLLM library's Mooncake integration, specifically targeting the insecure handling of serialized data in the recv_pyobj() function. This function uses pickle.loads() on data received over unsecured ZeroMQ sockets, which is a known method for Remote Code Execution (RCE) if the data is untrusted. The attacker can send malicious serialized data to trigger arbitrary code execution on the target system. This attack method aligns with MITRE ATT&CK Technique ID T1203, which covers exploitation for client execution, including exploiting software vulnerabilities to execute code remotely.
• T1059.006: Command and Scripting Interpreter: Python: The vulnerability involves the use of Python's pickle.loads() function on untrusted data, which is inherently insecure as it can deserialize data that leads to code execution. This aligns with MITRE ATT&CK Technique ID T1059.006, which covers the use of Python for execution. The attacker can craft serialized data that, when deserialized using pickle.loads(), executes arbitrary Python code.

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