Vulnerability Details CVE-2026-73559
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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.005
EPSS Ranking 43.7%
CVSS Severity
CVSS v3 Score 6.5
References
- https://github.com/vllm-project/vllm/commit/675f4295cdfe0d870471c2b51bfeca3a68a9569e
- https://github.com/vllm-project/vllm/pull/47845
- https://github.com/vllm-project/vllm/releases/tag/v0.26.0
- https://github.com/vllm-project/vllm/security/advisories/GHSA-87x5-vmc3-756j
- https://github.com/vllm-project/vllm/security/advisories/GHSA-87x5-vmc3-756j
Products affected by CVE-2026-73559
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cpe:2.3:a:vllm:vllm:0.19.0
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cpe:2.3:a:vllm:vllm:0.19.1
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cpe:2.3:a:vllm:vllm:0.19.2
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cpe:2.3:a:vllm:vllm:0.20.0
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cpe:2.3:a:vllm:vllm:0.20.1
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cpe:2.3:a:vllm:vllm:0.20.2
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cpe:2.3:a:vllm:vllm:0.21.0
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cpe:2.3:a:vllm:vllm:0.21.1
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cpe:2.3:a:vllm:vllm:0.22.0
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cpe:2.3:a:vllm:vllm:0.22.1
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cpe:2.3:a:vllm:vllm:0.23.0
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cpe:2.3:a:vllm:vllm:0.23.1
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cpe:2.3:a:vllm:vllm:0.24.0
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cpe:2.3:a:vllm:vllm:0.25.0
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cpe:2.3:a:vllm:vllm:0.25.1