6.9

CVSS Score

4.0

-

CVSS Score

Basic Information

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CVE-2026-54235

CVE-2026-54235: vLLM: temperature=NaN and temperature=Infinity bypass validation and propagate to GPU kernels

vLLM is an inference and serving engine for large language models (LLMs). Prior to 0.23.1rc0, ll temperature validation gates use comparison operators (<, >), which silently evaluate to False for NaN and for positive Infinity in Python's IEEE 754 float semantics. Both values pass every guard and propagate to GPU sampling kernels, where they produce undefined behavior or CUDA errors that can crash the inference worker. This vulnerability is fixed in 0.23.1rc0.

(GitHub Advisory)

Miggo Vulnerability Database

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CVE-2026-54235

CVE-2026-54235:

6.9

CVSS Score

4.0

-

CVSS Score

Basic Information

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Technical Details

SSVC / BOD 26-04 ↗

Exploitation NoneAutomatable YesTech Impact Partial

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Package Name	Ecosystem	Vulnerable Versions	First Patched Version
vllm	pip	<= 0.23.0

Technical Details

Vulnerability Intelligence
Miggo AI

Root Cause Analysis

The vulnerability is located in the _verify_args method of the SamplingParams class in vllm/sampling_params.py. This method is responsible for validating the parameters passed during the initialization of a SamplingParams object. The analysis of the provided patch commit d598d239737cfa37bcfcb98886ec3f3557fc7198 shows that the validation for the temperature and repetition_penalty parameters was insufficient. The original code relied on comparison operators (e.g., <) to validate these floating-point numbers. However, these checks are bypassed by non-finite values like NaN and Infinity due to the semantics of IEEE 754 floating-point arithmetic in Python. An attacker could provide temperature='nan' or temperature='inf' in a request, which would bypass the validation, propagate to the GPU kernels, and cause a crash, leading to a denial of service. The patch rectifies this by adding an explicit check using math.isfinite() for both temperature and repetition_penalty within the _verify_args method. This ensures that any non-finite values are caught and rejected. Therefore, the SamplingParams._verify_args function is identified as the vulnerable function because it is where the malformed input is processed without sufficient validation.

Vulnerable functions

SamplingParams._verify_args

vllm/sampling_params.py

The `_verify_args` method in the `SamplingParams` class was vulnerable because it did not properly validate the `temperature` and `repetition_penalty` parameters for non-finite values. The existing validation used comparison operators which evaluate to `False` for `NaN` and `Infinity`, allowing these values to pass. These non-finite values would then be passed to GPU kernels, causing a crash. The vulnerability is the lack of a check to ensure the values are finite.

Vulnerability Intelligence
Miggo AI

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WAF Protection Rules

WAF Rule

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Reasoning

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