CVE-2025-47277: vllm-project vllm Deserialization of Untrusted Data

Vulnerability summary

CVE-2025-47277 is a critical (CVSS 9.8) Deserialization of Untrusted Data vulnerability in vllm-project vllm. EPSS estimates a 0.96% chance of exploitation in the next 30 days, higher than 61% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 20-05-2025
   PublishedVulnerability first disclosed.
2. 20-05-2025
   Last modifiedVulnerability information updated.

Description

vLLM, an inference and serving engine for large language models (LLMs), has an issue in versions 0.6.5 through 0.8.4 that ONLY impacts environments using the `PyNcclPipe` KV cache transfer integration with the V0 engine. No other configurations are affected. vLLM supports the use of the `PyNcclPipe` class to establish a peer-to-peer communication domain for data transmission between distributed nodes. The GPU-side KV-Cache transmission is implemented through the `PyNcclCommunicator` class, while CPU-side control message passing is handled via the `send_obj` and `recv_obj` methods on the CPU side.​ The intention was that this interface should only be exposed to a private network using the IP address specified by the `--kv-ip` CLI parameter. The vLLM documentation covers how this must be limited to a secured network. The default and intentional behavior from PyTorch is that the `TCPStore` interface listens on ALL interfaces, regardless of what IP address is provided. The IP address given was only used as a client-side address to use. vLLM was fixed to use a workaround to force the `TCPStore` instance to bind its socket to a specified private interface. As of version 0.8.5, vLLM limits the `TCPStore` socket to the private interface as configured.

• CWE-502Deserialization of Untrusted DataThe product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.