Reference page — cumulative record through Saturday, October 3, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2026-73559

CVE-2026-73559MEDIUM

vllm-project vllm — vLLM: Completion prompt lists fan out into unbounded engine requests

  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   N   L   L   N  U  N  N  H    6.5   .0058   45.9     —

AFFECTED
  Product  Versions               Fixed
  vllm     >= 0.19.0, < 0.26.0 –  —

TIMELINE
  Aug 12  Reserved by GitHub_M
  Aug 13  Published (CNA: GitHub_M)
  Sep 28  EXPLOIT PUBLISHED — CVE-2026-73559 (vllm-project vllm). Public exploit reference added.

CWE-400 · CNA: GitHub_M · CVSS v3.1 · 4 references · NVD status: Analyzed

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.

Lifecycle

Complete event history — 3 events, chronological
Date	Event	Detail
August 12, 2026	Reserved	Reserved by GitHub_M
August 13, 2026	Published	Published (CNA: GitHub_M)
September 28, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2026-73559 (vllm-project vllm). Public exploit reference added.

Affected

Affected products and packages — 1 row
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
vllm-project	vllm	—	>= 0.19.0, < 0.26.0	—

Weaknesses

CWE-400

References (4)

https://github.com/vllm-project/vllm/commit/675f4295cdfe0d870471c2b51bfeca3a68a9569e [Patch]
https://github.com/vllm-project/vllm/pull/47845 [Issue Tracking, Patch]
https://github.com/vllm-project/vllm/releases/tag/v0.26.0 [Release Notes]
https://github.com/vllm-project/vllm/security/advisories/GHSA-87x5-vmc3-756j [Exploit, Vendor Advisory]

Authoritative record: CVE-2026-73559 at cve.org

Vendors: vllm-project

Weaknesses: CWE-400

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-73559 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Saturday, October 3, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.