CVE-2026-48746

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.

What this means for your business

It affects Vllm. It matters if your company, or a supplier that handles your data, runs it.
An attacker can use it remotely, over a network, without a login, and without anyone at your company clicking anything.
FIRST's prediction model gives it a 1% chance of attack attempts being seen in the next 30 days, ranking above 65% of all known flaws.

What to do

1Check whether your company or your suppliers run Vllm, and which version. The affected versions are listed further down this page.
2If you do, follow the vendor's guidance. No patch reference has been published yet.

Not sure if your company is exposed?

Fastnexa’s certified penetration testers can check whether attackers could use this flaw, or others like it, against your websites, apps and network. The full test is free for our first 10 founding clients until 31 December 2026.

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Scoring

CVSS: 9.1 (v3.1)
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Weakness: CWE-444
Assigned by: security-advisories@github.com

Dates

Published: 2026-06-22
Last modified: 2026-09-16
Sources: NVD

Affected products

Vllm Vllm0.3.0 - 0.22.0

As listed in the NVD configuration data. Not a statement about your estate.