CVE-2026-73559
Published:August 13, 2026
Updated:August 31, 2026
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 Packages
vllm (CONDA):
Affected version(s) >=0.19.1 <0.26.0Fix Suggestion:
Update to version 0.26.0https://github.com/vllm-project/vllm.git (GITHUB):
Affected version(s) >=v0.19.0 <v0.26.0Fix Suggestion:
Update to version v0.26.0vllm (PYTHON):
Affected version(s) >=0.19.0 <0.26.0Fix Suggestion:
Update to version 0.26.0Related Resources (9)
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Contact UsCVSS v4
Base Score:
7.1
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
LOW
User Interaction
NONE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
NONE
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
6.5
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Weakness Type (CWE)
Uncontrolled Resource Consumption
EPSS
Base Score:
0.39