---
title: "CVE-2026-48746: vLLM: OpenAI auth bypass"
url: https://erroneo.us/security/cve/CVE-2026-48746/
description: "CVE-2026-48746 (vllm (PyPI)): 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…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-06-22
date_modified: 2026-09-16
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-48746"
kev: false
cvss: 9.1
epss: 0.01152
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-48746: vLLM: OpenAI auth bypass

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Not in CISA KEV , but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 1.2% , percentile 67: FIRST’s model estimates a 1.2% chance of exploitation activity in the next 30 days, higher than 67% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes vllm (PyPI) >= 0.3.0, < 0.22.0, fixed in 0.22.0 . Check your lockfile, including transitive dependencies.

## What it is

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 VLLMAPIKEY or --api-key. This vulnerability is fixed in 0.22.0.

## Affected packages

- PyPI `vllm` >= 0.3.0, < 0.22.0 → fixed: 0.22.0

## Affected products (CVE record)

- vllm-project vllm: >= 0.3.0, < 0.22.0

## Severity

- GitHub_M CVSS 3.1: 9.1 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H`
- redhat-SADP CVSS 3.1: 9.1 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H`
- GitHub CVSS 3.1: 9.1 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc , automatable yes , technical impact partial .
- FIRST EPSS (model of 2026-10-21): 1.15% probability of exploitation activity in the next 30 days; percentile 67.

## Sources

- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:61627)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:36005)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:61629)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:36006)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:30089)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:30088)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:42132)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:42142)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:43038)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:42644)
- [GitHub Advisory GHSA-94f4-hr76-p5j6](https://github.com/advisories/GHSA-94f4-hr76-p5j6)
- [CVE.org record CVE-2026-48746](https://www.cve.org/CVERecord?id=CVE-2026-48746)
- [NVD entry CVE-2026-48746](https://nvd.nist.gov/vuln/detail/CVE-2026-48746)
- [github.com](https://github.com/vllm-project/vllm/security/advisories/GHSA-94f4-hr76-p5j6)
- [github.com](https://github.com/vllm-project/vllm/pull/43426)
- [x41-dsec.de](https://x41-dsec.de/lab/advisories/x41-2026-002-starlette)
- [access.redhat.com](https://access.redhat.com/security/cve/CVE-2026-48746)
- [RHBZ#2491581](https://bugzilla.redhat.com/show_bug.cgi?id=2491581)
- [security.access.redhat.com](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-48746.json)
- [github.com](https://github.com/pypa/advisory-database/tree/main/vulns/vllm/PYSEC-2026-226.yaml)

---
Source page: https://erroneo.us/security/cve/CVE-2026-48746/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt