---
id: CVE-2026-73559
title: vLLM is an inference and serving engine for large language models
summary: >-
  vLLM is an inference and serving engine for large language models. From 0.19.0
  until 0.26.0, the /v1/completions CompletionRequest.prompt field in
  vllm/entrypoints/openai/completion/protocol.py accepts an unbounded list[str]
  or list[list…
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-400
  - CWE-770
vendor: vllm
product: vllm
affected:
  - 'vllm >= 0.19.0, < 0.26.0'
patched:
  - vllm 0.26.0
published: '2026-08-13'
updated: '2026-09-28'
sourceUpdated: '2026-09-28T18:41:23.210'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-73559'
references:
  - url: >-
      https://github.com/vllm-project/vllm/commit/675f4295cdfe0d870471c2b51bfeca3a68a9569e
    label: security-advisories@github.com
  - url: 'https://github.com/vllm-project/vllm/pull/47845'
    label: security-advisories@github.com
  - url: 'https://github.com/vllm-project/vllm/releases/tag/v0.26.0'
    label: security-advisories@github.com
  - url: >-
      https://github.com/vllm-project/vllm/security/advisories/GHSA-87x5-vmc3-756j
    label: security-advisories@github.com
  - url: >-
      https://github.com/vllm-project/vllm/security/advisories/GHSA-87x5-vmc3-756j
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-73559'
  - url: 'https://github.com/advisories/GHSA-87x5-vmc3-756j'
  - url: 'https://github.com/vllm-project/vllm'
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-73559.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-73559'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2515421'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-73559'
  - url: 'https://access.redhat.com/errata/RHSA-2026:82415'
  - url: 'https://access.redhat.com/errata/RHSA-2026:82368'
  - url: 'https://access.redhat.com/errata/RHSA-2026:82061'
  - url: 'https://access.redhat.com/errata/RHSA-2026:82059'
  - url: 'https://access.redhat.com/errata/RHSA-2026:82371'
tags:
  - nvd
  - ghsa
  - pip
  - osv
  - csaf
  - vex
  - red-hat
aliases:
  - GHSA-87x5-vmc3-756j
  - PYSEC-2026-3704
ecosystem: pip
ingestedAt: '2026-08-13T19:05:04.705Z'
epss: 0.00583
epssPercentile: 0.47671
---

## Overview

vLLM is an inference and serving engine for large language models. From 0.19.0 until 0.26.0, the /v1/completions CompletionRequest.prompt field in vllm/entrypoints/openai/completion/protocol.py accepts an unbounded list[str] or list[list[int]], prompt_to_seq() in vllm/renderers/inputs/preprocess.py and OnlineRenderer.preprocess_completion() in vllm/renderers/online_renderer.py expand every element, and vllm/entrypoints/openai/completion/serving.py creates one engine generator and response slot per prompt, allowing an authenticated API client to exhaust CPU, memory, async scheduling capacity, engine request slots, and response buffering with one request. This issue is fixed in version 0.26.0.

## Affected

- `vllm >= 0.19.0, < 0.26.0`

## Remediation

Upgrade past the affected range:

- `vllm 0.26.0`

## Package advisory (CVE-2026-73559)

Affected packages:

- `vllm >= 0.19.0, < 0.26.0`

Patched in:

- `vllm 0.26.0`

Source: https://github.com/advisories/GHSA-87x5-vmc3-756j

## Vendor advisories

- **RHSA-2026:82415** · Red Hat · fixed in: Red Hat AI Inference Server 3.5 · released 2026-10-13 · [advisory](https://access.redhat.com/errata/RHSA-2026:82415)
- **RHSA-2026:82368** · Red Hat · fixed in: Red Hat AI Inference Server 3.5 · released 2026-10-13 · [advisory](https://access.redhat.com/errata/RHSA-2026:82368)
- **RHSA-2026:82061** · Red Hat · fixed in: Red Hat AI Inference Server 3.5 · released 2026-10-13 · [advisory](https://access.redhat.com/errata/RHSA-2026:82061)
- **RHSA-2026:82059** · Red Hat · fixed in: Red Hat AI Inference Server 3.5 · released 2026-10-13 · [advisory](https://access.redhat.com/errata/RHSA-2026:82059)
- **RHSA-2026:82371** · Red Hat · fixed in: Red Hat AI Inference Server 3.5 · released 2026-10-13 · [advisory](https://access.redhat.com/errata/RHSA-2026:82371)
- **Red Hat VEX** · Moderate · affected: Red Hat OpenShift AI (RHOAI) · no fix planned: Red Hat OpenShift AI (RHOAI) · updated 2026-10-14 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-73559.json)