CVE-2026-116176
Received Received - Intake

Server-Side Request Forgery in vLLM

Publication date: 2026-10-25

Last updated on: 2026-10-25

Assigner: VulnCheck

Description
vLLM from 0.9.2 before 0.24.0 contains a server-side request forgery vulnerability that allows API callers to force outbound connections by embedding a decode address in the X-Request-Id header. Attackers can make a P2pNcclConnector prefill worker ZMQ-connect to an attacker host, leaking the NCCL unique_id and KV-cache tensors or blocking the worker.

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Meta Information

Published
2026-10-25
Last Modified
2026-10-25
Generated
2026-10-25
AI Q&A
2026-10-25
EPSS Evaluated
N/A
NVD
CVE-2026-116176
EUVD
EUVD-2026-109437

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
vllm-project vllm 0.9.2

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Exploitability

CWE
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KEV
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CWE ID Description
CWE-918 The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.

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Executive Summary

CVE-2026-116176 is a Server-Side Request Forgery (SSRF) vulnerability in vLLM versions 0.9.2 through 0.23.9. It allows attackers to manipulate the X-Request-Id header to force the system to make outbound ZMQ connections to arbitrary hosts. This can leak sensitive data like NCCL unique_id and KV-cache tensors or block worker processes.

Detection Guidance

To detect this vulnerability, monitor network traffic for unexpected outbound ZMQ connections from vLLM processes, particularly to unrecognized hosts. Check logs for unusual X-Request-Id headers containing host:port values. Inspect vLLM configurations for the --kv-transfer-config flag, which enables the vulnerable P2pNcclConnector.

Impact Analysis

Attackers can steal sensitive data such as KV-cache tensors containing prompt text and hidden states. They can also cause denial-of-service by blocking worker processes. Exploitation requires the P2pNcclConnector to be enabled and may need a valid API key depending on configuration.

Compliance Impact

This vulnerability could lead to unauthorized access to sensitive data, potentially violating GDPR (data protection) and HIPAA (health information privacy) by exposing personal or health-related information through leaked KV-cache tensors.

Mitigation Strategies

Upgrade vLLM to version 0.24.0 or later. If upgrading is not possible, disable the P2pNcclConnector by removing the --kv-transfer-config flag. Strip or replace the X-Request-Id header with a random UUID when the connector is active. Validate remote addresses against an allow-list before opening ZMQ sockets.

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