CVE-2026-115916

vLLM: Out-of-vocabulary prompt token id passes input validation and triggers a CUDA device-side assert (engine crash / DoS)

MEDIUM
6.5
CVSS Score
Published: October 26, 2026 at 05:18 PM UTC
Updated: October 28, 2026 at 03:36 PM UTC
1 product affected across 1 vendorvLLM

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Severity
MEDIUM6.5
Exploit prediction
EPSS 0.3%

Description

vLLM is an inference and serving engine for large language models. Prior to 0.32.0, vllm/tokenizers/hf.py computes max_token_id with an off-by-one upper bound, allowing a pre-tokenized prompt ID equal to the vocabulary size to pass validation. For a tensor-parallel size of one and an exact multiple-of-64 vocabulary, VocabParallelEmbedding.forward does not mask that value before F.embedding uses it, causing a CUDA device-side assertion and terminating the engine. This issue is fixed in version 0.32.0.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 0.32.0

References (4)

x_refsource_CONFIRMPatchVendor Advisory
Source: cverecord
https://github.com/vllm-project/vllm/security/advisories/GHSA-q97c-p368-75c4
x_refsource_MISCPatch
Source: cverecord
https://github.com/vllm-project/vllm/pull/59491
x_refsource_MISCRelease Notes
Source: cverecord
https://github.com/vllm-project/vllm/releases/tag/v0.32.0

CVSS

6.5MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-129CWE-193

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