CVE-2026-115916
Description
A flaw was found in vLLM. This vulnerability allows a remote attacker to cause a Denial of Service (DoS) by submitting a request containing an out-of-bounds pre-tokenized prompt token identifier. Due to an off-by-one error in input validation, an invalid token identifier equal to the vocabulary size is accepted, which triggers an assertion failure during embedding processing and terminates the inference engine.
Statement
Red Hat has rated this issue as Moderate severity because it results exclusively in a denial of service by terminating the model serving process without allowing unauthorized data access, privilege escalation, or system compromise. In environments such as Red Hat OpenShift AI and Red Hat AI Inference Server, exploitation is limited to configurations utilizing single-GPU instances (tensor parallelism of one) hosting specific models with vocabularies aligned to multiples of 64. Furthermore, multi-GPU deployments with higher tensor parallelism mask token inputs, which naturally prevents the crash condition.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 6.5 | N/A | 6.5 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | Low | N/A | Low |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | None |
| Integrity Impact | None | N/A | None |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
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