Description
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.
Published: 2026-08-13
Score: 6.5 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-87x5-vmc3-756j vLLM: Completion prompt lists fan out into unbounded engine requests
History

Sat, 15 Aug 2026 00:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-770
References
Metrics threat_severity

None

threat_severity

Moderate


Thu, 13 Aug 2026 18:00:00 +0000

Type Values Removed Values Added
First Time appeared Vllm-project
Vllm-project vllm
Vendors & Products Vllm-project
Vllm-project vllm

Thu, 13 Aug 2026 15:45:00 +0000

Type Values Removed Values Added
Description 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.
Title vLLM: Completion prompt lists fan out into unbounded engine requests
Weaknesses CWE-400
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}


Subscriptions

Vllm-project Vllm
cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-08-14T16:51:35.047Z

Reserved: 2026-08-12T20:53:46.380Z

Link: CVE-2026-73559

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-13T16:19:05.863

Modified: 2026-08-14T17:20:33.493

Link: CVE-2026-73559

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-08-13T15:09:02Z

Links: CVE-2026-73559 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-08-15T02:00:04Z

Weaknesses
  • CWE-400

    Uncontrolled Resource Consumption

  • CWE-770

    Allocation of Resources Without Limits or Throttling