CVE-2026-48746
Received Received - Intake
Authentication Bypass in vLLM via ASGI Server

Publication date: 2026-06-22

Last updated on: 2026-06-22

Assigner: GitHub, Inc.

Description
vLLM is an inference and serving engine for large language models (LLMs). From 0.3.0 until 0.22.0, a vulnerability in ASGI web servers and starlette's trust on those web servers enables an authentication bypass of the OpenAI API AuthenticationMiddleware. It allows to use the API without providing the configured VLLM_API_KEY or --api-key. This vulnerability is fixed in 0.22.0.
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Meta Information
Published
2026-06-22
Last Modified
2026-06-22
Generated
2026-06-23
AI Q&A
2026-06-23
EPSS Evaluated
N/A
NVD
CVE-2026-48746
Affected Vendors & Products
Currently, no data is known.
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-444 The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination.
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Compliance Impact

This vulnerability allows authentication bypass of the OpenAI API AuthenticationMiddleware in vLLM, enabling unauthorized use of the API without the required API key.

Such unauthorized access could lead to exposure or misuse of sensitive data processed by the API, potentially violating data protection requirements under standards like GDPR or HIPAA.

Therefore, this vulnerability may negatively impact compliance with regulations that mandate strict access controls and protection of sensitive information.

Impact Analysis

The vulnerability allows unauthorized users to access the API without authentication, which can lead to unauthorized use of the service. Given the CVSS score of 9.1 with high confidentiality and availability impacts, this could result in data exposure or denial of service, potentially disrupting operations or exposing sensitive information.

Mitigation Strategies

To mitigate this vulnerability, upgrade vLLM to version 0.22.0 or later, where the authentication bypass issue has been fixed.

Executive Summary

This vulnerability affects vLLM, an inference and serving engine for large language models. Specifically, from versions 0.3.0 until 0.22.0, a flaw in ASGI web servers and the way starlette trusts those servers allows an authentication bypass in the OpenAI API AuthenticationMiddleware. This means that an attacker can use the API without providing the required VLLM_API_KEY or --api-key.

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