CVE-2026-73559
MediumCVSS 6.5Exploitation Probability (EPSS)
Low risk32th percentile - higher than 32% of all known CVEs
Summary
vLLM is an inference and serving engine for large language models. From 0.19.0 until 0.26.0, the prompt field in CompletionRequest in /v1/completions accepts an unbounded list of strings or ints, and functions prompt_to_seq() and OnlineRenderer.preprocess_completion() expand every element, causing the server to create one engine generator and response slot per prompt. An authenticated API client can exhaust CPU, memory, async scheduling capacity, engine request slots, and response buffering with one request. This issue is fixed in version 0.26.0.
Risk Assessment
The risk is the possibility of a DoS attack by an authenticated user, which could lead to service unavailability for other users.
Recommendation
It is recommended to upgrade vLLM to version 0.26.0 or later, which includes a fix limiting the number of prompts.
Original NVD description (English source)
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.